Positive photosensitive composition

ABSTRACT

A positive photosensitive composition comprising (A) a compound which generates an acid upon irradiation with an actinic ray or radiation, and (B-1) a resin having a group which is decomposed by the action of an acid to increase solubility in an alkaline developing solution and containing at least one structure represented by formulae (I), (II) and (III) as described in the specification or (B-2) a resin having at least one monovalent polyalicyclic group represented by formula (Ib) as described in the specification and a group which is decomposed by the action of an acid to increase solubility in an alkaline developing solution. The positive photosensitive composition containing the resin according to the present invention has high transmittance to far ultraviolet light particularly having a wavelength of 220 nm or less and exhibits good dry etching resistance. Further, the positive photosensitive composition exhibits high sensitivity, good resolution and good pattern profile when far ultraviolet light having a wavelength of 250 nm or less, particularly 220 nm or less (especially an ArF excimer laser beam) is employed as an exposure light source, and thus it can be effectively employed for the formation of fine pattern necessary for the production of semiconductor elements.

FIELD OF THE INVENTION

[0001] The present invention relates to a positive photosensitivecomposition for use in the production of a semiconductor such as IC, inthe production of a circuit board such as liquid crystal and thermalhead and in other photofabrication processes. More specifically, thepresent invention relates to a positive photosensitive compositionsuitable for use in a case where an exposure light source used is a farultraviolet beam of 250 nm or less.

BACKGROUND OF THE INVENTION

[0002] A positive photoresist composition commonly used is a compositioncomprising an alkali-soluble resin and a naphthoquinonediazide compoundas a photosensitive material. Examples thereof include a “novolak-typephenol resin/naphthoquinonediazide-substituted compound” described inU.S. Pat. Nos. 3,666,473, 4,115,128 and 4,173,470 and a “novolak resincomprisingcresol-formaldehyde/trihydroxybenzophenone-1,2-naphthoquinonediazidesulfonic acid ester” as a most typical composition, described in L. F.Thompson, Introduction to Microlithography, No. 2, 19, pp. 112-121, ACSPublishing.

[0003] In these positive photoresists fundamentally comprising a novolakresin and a quinonediazide compound, the novolak resin exhibits highresistance against plasma etching and the naphthoquinonediazide compoundacts as a dissolution inhibitor. The naphthoquinonediazide generates acarboxylic acid on irradiation of light and loses its dissolutioninhibiting ability to thereby elevate the alkali solubility of thenovolak resin.

[0004] From this viewpoint, a large number of positive photoresistscomprising a novolak resin and a naphthoquinonediazide-basephotosensitive material have heretofore been developed and used inpractice, and satisfactory results can be obtained in the working for aline width of approximately from 0.8 to 2 μm.

[0005] However, integrated circuits are being more and more intensifiedin the integration degree and the production of a semiconductorsubstrate such as VLSI requires working of an ultrafine patterncomprising lines having a width of a half micron or less.

[0006] According to one of known techniques for achievingminiaturization of a pattern, a resist pattern is formed using anexposure light source having a shorter wavelength. This technique can bedescribed using the following Rayleigh's formula showing the resolutionR (line width) of an optical system:

R=k·λk/NA

[0007] (wherein λ is a wavelength of the exposure light source, NA is anumerical aperture of the lens and k is a process constant). As isapparent from this formula, a higher resolution, namely, a smaller Rvalue can be obtained by reducing the wavelength X of the exposure lightsource.

[0008] For example, in the production of a DRAM having an integrationdegree up to 64 M bits, the i beam (365 nm) of a high-pressure mercurylamp is used at present as the light source. In the mass production of256-M bit DRAMs, use of a KrF excimer laser (248 nm) in place of thei-line has been studied. Further, for the purpose of producing DRAMshaving an integration degree of 1 G bits or more, a light source havinga further shorter wavelength has been investigated. To this effect, anArF excimer laser (193 nm), an F₂ excimer laser (157 nm), an X ray, anelectron beam and the like are considered to be effective (see, TakumiUeno et al., Tanpacho Photoresist Zairyo-ULSI Ni Muketa BisaiKako-(Short Wavelength Photoresist Material-Fine Working Toward ULSI-),Bunshin Shuppan (1988).

[0009] When a conventional resist comprising a novolak resin and anaphthoquinonediazide compound is used for the pattern formation byphotolithography with a far ultraviolet ray or excimer laser beam, thenovolak resin and naphthoquinonediazide compound exhibit strongabsorption in the far ultraviolet region and the light scarcely reachesthe bottom of resist, as a result, the resist has low sensitivity andonly a tapered pattern can be obtained.

[0010] One of the techniques for solving this problem is the chemicalamplification-type resist composition described in U.S. Pat. No.4,491,628 and European Patent No. 249,139. The chemicalamplification-type positive resist composition is a pattern formationmaterial which generates an acid in the exposed area on irradiation ofradiation such as far ultraviolet ray and due to the reaction using theacid as a catalyst, differentiates solubility in a developer between thearea irradiated with the active radiation and the non-irradiated area toform a pattern on a substrate.

[0011] Examples thereof include combinations of a compound capable ofgenerating an acid by photolysis with an acetal or O,N-acetal compound(see, JP-A-48-89003 (the term “JP-A” as used herein means an “unexaminedpublished Japanese patent application”), with an ortho ester or amideacetal compound (JP-A-51-120714), with a polymer having an acetal orketal group on the main chain (JP-A-53-133429), with an enol ethercompound (JP-A-55-12995), with an N-acyliminocarbonic acid compound(JP-A-55-126236), with a polymer having an ortho ester group on the mainchain (JP-A-56-17345), with a tertiary alkyl ester compound(JP-A-60-3625), with a silyl ester compound (JP-A-60-10247) or with asilyl ether compound (JP-A-60-37549, JP-A-60-121446). These combinationsin principle have a quantum yield exceeding 1 and therefore exhibit highphotosensitivity.

[0012] A system which decomposes by heating in the presence of an acidand is alkali-solubilized is also used and examples thereof includecombinations of a compound capable of generating an acid on exposurewith an ester or carbonic acid ester compound having a tertiary orsecondary carbon (e.g., tert-butyl, or 2-cyclohexenyl) described, forexample, in JP-A-59-45439, JP-A-60-3625, JP-A-62-229242, JP-A-63-27829,JP-A-63-36240, JP-A-63-250642, JP-A-5-181279, Polym. Eng. Sce., Vol. 23,page 1012 (1983), ACS. Sym., Vol. 242, page 11 (1984), SemiconductorWorld, November, 1987, page 91, Macromolecules, Vol. 21, page 1475(1988), and SPIE, Vol. 920, page 42 (1988), with an acetal compounddescribed, for example, in JP-A-4-219757, JP-A-5-249682 andJP-A-6-65332, or with a tert-butyl ether compound described, forexample, in JP-A-4-211258 and JP-A-6-65333.

[0013] Such systems are mainly composed of a resin having a basicskeleton of poly(hydroxystyrene) which is small in the absorption in theregion of 248 nm and therefore, when the exposure light source is a KrFexcimer laser, they have high sensitivity and high resolution and arecapable of forming a good pattern. Thus they can form good systems ascompared with conventional naphthoquinonediazide/novolak resin systems.

[0014] However, when the light source has a still shorter wavelength,for example, when the exposure light source used is an ArF excimer laser(193 nm), the above-described chemical amplification systems are yetdeficient because the compound having an aromatic group substantiallyhas large absorption in the region of 193 nm. As a polymer having smallabsorption in the 193 nm region, in J. Vac. Sci. Technol., B9, 3357(1991), the use of poly(meth)-acrylate is described. However, thispolymer has a problem in that the resistance against dry etching whichis commonly performed in the production process of semi-conductors islow as compared with conventional phenol resins having aromatic groups.

[0015] In Proc. of SPIE, 1672, 66 (1922), it is reported that polymershaving alicyclic groups exhibit the dry etching resistance on the samelevel as that of the compounds having aromatic groups and at the sametime, have small absorption in the 193 nm region. The use of thesepolymers has been aggressively studied in recent years. Specificexamples thereof include the polymers described, for example, inJP-A-4-39665, JP-A-5-80515, JP-A-5-265212, JP-A-5-297591, JP-A-5-346668,JP-A-6-289615, JP-A-6-324494, JP-A-7-49568, JP-A-7-185046,JP-A-7-191463, JP-A-7-199467, JP-A-7-234511, JP-A-7-252324,JP-A-8-259626, JP-A-9-73173 and JP-A-9-90637. However, these polymers donot always have sufficient dry etching resistance and aredisadvantageous in that the synthesis thereof necessitates many steps.

[0016] Further, the introduction of the alicyclic group in order toimprove the dry etching resistance is accompanied with the decrease inadhesion to a substrate and causes a problem in that peeling off of theresist layer occurs in the pattern after development. In order to solvesuch a problem, a resin containing a unit having a γ-butyrolactonestructure is proposed as described in EP-A-856773. Although the adhesionis improved by using the resin, it has only a low acid decomposingproperty due to the secondary carboxylic acid ester, resulting indecrease in sensitivity and exhibits insufficiently low resolution.Further, since the hydrophobic property of the resist layer increases bythe introduction of the alicyclic group, such a resist composition hasanother problem of the occurrence of development defects.

SUMMARY OF THE INVENTION

[0017] Therefore, an object of the present invention is to provide apositive photosensitive composition suitable for use of an exposurelight source having a wavelength of 250 nm or less, particularly 220 nmor less.

[0018] Another object of the present invention is to provide a positivephotosensitive composition which provides good sensitivity, resolution,adhesion and resist pattern and exhibits sufficient dry etchingresistance when used with an exposure light source having a wavelengthof 250 nm or less, particularly 220 nm or less.

[0019] Other objects of the present invention will become apparent fromthe following description.

[0020] As a result of intensive investigations made by the inventors onpositive photosensitive compositions while taking the propertiesdescribed above into consideration, it has been found that the objectsof the present invention are successfully accomplished by using a resinhaving a specific alicyclic group described below, to complete thepresent invention.

[0021] Specifically, the present invention comprises a positivephotosensitive composition which comprises (A) a compound whichgenerates an acid upon irradiation with an actinic ray or radiation, and(B) a resin having a group which is decomposed by the action of an acidto increase solubility in an alkaline developing solution and furthercontaining a group having the specific alicyclic structure.

[0022] A first embodiment of the positive photosensitive compositionaccording to the present invention includes the following:

[0023] (1) a positive photosensitive composition comprising (A) acompound which generates an acid upon irradiation with an actinic ray orradiation, and (B) a resin having a group which is decomposed by theaction of an acid to increase solubility in an alkaline developingsolution, wherein the resin contains at least one structure representedby the following formulae (I), (II) and (III):

[0024] wherein R₁ and R₂, which may be the same or different, eachrepresents a hydrogen atom or an optionally substituted straight-chain,branched chain or cyclic alkyl group, or R₁ and R₂ may be bonded to eachother to form a monocyclic or polycyclic ring which may contain anoxygen atom, a sulfur atom, a nitrogen atom, a ketone bond, an esterbond, an imido bond or an amido bond as a linking group; R₃, R₄ and R₅,which may be the same or different, each represents a hydrogen atom, anoptionally substituted straight-chain, branched chain or cyclic alkyl oralkoxy group, or two or more of R₃, R₄ and R₅ may be bonded to eachother to form a monocyclic or polycyclic ring which may contain anoxygen atom, a sulfur atom, a nitrogen atom, a ketone bond, an esterbond, an imido bond or an amido bond as a linking group; X represents asingle bond or a divalent linking group, or X and either or both of R₁and R₂ may be bonded to each other to form a monocyclic or polycyclicring; Y represents an oxygen atom, a sulfur atom, —NH—, —N(OH)— or—N(alkyl)—; and n represents an integer of from 1 to 3;

[0025] (2) a positive photosensitive composition comprising (A) acompound which generates an acid upon irradiation with an actinic ray orradiation, (B) a resin having a group which is decomposed by the actionof an acid to increase solubility in an alkaline developing solution,and (C) a low molecular weight compound having a molecular weight of3,000 or less and having a group which is decomposed by the action of anacid to increase solubility in an alkaline developing solution, whereinthe resin (B) and/or the low molecular weight compound (C) contain atleast one structure represented by formulae (I), (II) and (III)described in item (1) above;

[0026] (3) a positive photosensitive composition as described in item(1) or (2) above, wherein the resin having a group which is decomposedby the action of an acid to increase solubility in an alkalinedeveloping solution is (D) a resin which contains at least one repeatingunit having the structure represented by formula (I), (II) or (III) anda repeating unit having a monoalicyclic or polyalicyclic hydrocarbonmoiety;

[0027] (4) a positive photosensitive composition as described in item(1), (2) or (3), wherein the monoalicyclic or polyalicyclic hydrocarbonmoiety is an adamantane residue;

[0028] (5) a positive photosensitive composition as described in any oneof items (1) to (4), wherein the resin having a group which isdecomposed by the action of an acid to increase solubility in analkaline developing solution contains a structure represented by formula(a):

[0029] wherein R₁, R₂, R₃, R₄ and R₅, and n are the same as defined informula (I), and R₁₅ represents a hydrogen atom, a halogen atom, a cyanogroup, an alkyl group or a haloalkyl group;

[0030] (6) the positive photosensitive composition as described in anyone of items (1) to (5), wherein the resin having a group which isdecomposed by the action of an acid to increase solubility in analkaline developing solution contains a structure represented by formula(b):

[0031] wherein R₁, R₂, R₃, R₄ and R₅, and n are the same as defined informula (I), and R₁₅ represents a hydrogen atom, a halogen atom, a cyanogroup, an alkyl group or a haloalkyl group;

[0032] wherein R₁₅ in formulae a and b are the same as R₁₅ in formula(IV) described later;

[0033] (7) a positive photosensitive composition comprising (A) acompound which generates an acid upon irradiation with an actinic ray orradiation, (C) a low molecular weight compound having a molecular weightof 3,000 or less and having a group which is decomposed by the action ofan acid to increase solubility in an alkaline developing solution, and(E) a resin which is insoluble in water but soluble in an alkalinedeveloping solution, wherein the low molecular weight compound (C)contains at least one structure represented by formulae (I), (II) and(III) described in item (1) above;

[0034] (8) a positive photosensitive composition as described in any oneof items (1) to (7) above, wherein R₁ and R₂ each represents asubstituent other than a hydrogen atom;

[0035] (9) a positive photosensitive composition as described in any oneof items (1) to (7) above, wherein the composition further comprises (F)a fluorine-base and/or silicon-base surface active agent;

[0036] (10) a positive photosensitive composition as described in anyone of items (1) to (7) above, wherein the composition is suitable forexposure using far ultraviolet light having a wavelength of 250 nm orless as an exposure light source; and

[0037] (11) a positive photosensitive composition as described in anyone of items (1) to (7) above, wherein the composition is suitable forexposure using far ultraviolet light having a wavelength of 220 nm orless as an exposure light source.

[0038] A second embodiment of the positive photosensitive compositionaccording to the present invention includes the following:

[0039] (1) a positive photosensitive composition comprising (A) acompound which generates an acid upon irradiation with an actinic ray orradiation and (B) a resin having at least one monovalent polyalicyclicgroup represented by the following formula (Ib) and a group which isdecomposed by the action of an acid to increase solubility in analkaline developing solution:

[0040] wherein R_(a), R_(b), R_(c), R_(d), R_(e), R_(f) and R_(g), whichmay be the same or different, each represents an optionally substitutedalkyl, cycloalkyl, alkenyl or alkynyl group, a halogen atom, a cyanogroup, —R_(6b)—O—R_(7b), —R_(8b)—CO—O—R_(9b),—R_(10b)—CO—NR_(11b)R_(12b) or —R_(13b)—O—CO—R_(14b); R_(7b) and R_(9b),which may be the same or different, each represents a hydrogen atom, anoptionally substituted alkyl, cycloalkyl or alkenyl group or a groupwhich is decomposed by the action of an acid to increase solubility inan alkaline developing solution; R_(11b), R_(12b) and R_(14b), which maybe the same or different, each represents a hydrogen atom, an optionallysubstituted alkyl, cycloalkyl or alkenyl group, or R_(11b) and R_(12b)may be bonded to each other to form a ring; R_(6b), R_(8b), R_(10b) andR_(13b), which may be the same or different, each represents a singlebond, an optionally substituted alkylene, alkenylene or cycloalkylenegroup; two of R_(a) to R_(g), which are present on the same carbon atom,may represent in combination a carbonyl group (═O) or a thiocarbonylgroup (═S); two of R_(a) to R_(g), which are bonded to adjacent carbonatoms, may be bonded to each other to form a double bond between thesetwo carbon atoms; at least two of R_(a) to R_(g) may be bonded to eachother to form a ring; and the monovalent polyalicyclic group representedby formula (Ib) may be connected to the resin moiety in any positionthereof;

[0041] (2) a positive photosensitive composition as described in item(1) above, wherein the resin (B) is a resin comprising at least onerepeating unit represented by the following formulae (IVb), (Vb) and(VIb) and a group which is decomposed by the action of an acid toincrease solubility in an alkaline developing solution:

[0042] wherein R_(15b), R_(16b) and R_(18b) to R_(20b), which may be thesame or different, each represents a hydrogen atom, a halogen atom, acyano group, an alkyl group or a haloalkyl group; R_(17b) represents acyano group, —CO—OR_(27b) or —CO—NR_(28b)R_(29b); X_(1b), X_(2b) andX_(3b), which may be the same or different, each represents a singlebond, an optionally substituted divalent alkylene, alkenylene orcycloalkylene group, —O—, —SO₂—, —O—CO—R_(30b)—, —CO—O—R_(31b)—, or—CO—NR_(32b)—R_(33b)—; R_(27b) represents a hydrogen atom, an optionallysubstituted alkyl, cycloalkyl or alkenyl group, or a group which isdecomposed by the action of an acid to increase solubility in analkaline developing solution; R_(28b), R_(29b) and R_(32b), which may bethe same or different, each represents a hydrogen atom or an optionallysubstituted alkyl, cycloalkyl or alkenyl group, or R_(28b) and R_(29b)may be bonded to each other to form a ring; R_(30b), R_(31b) andR_(33b), which may be the same or different, each represents a singlebond or a divalent alkylene, alkenylene or cycloalkylene group, or adivalent group formed by combining each of these groups with an ether,ester, amido, urethane or ureido group; and Y_(b) represents thepolyalicyclic group represented by formula (Ib) described in item (1)above;

[0043] (3) a positive photosensitive composition as described in item(1) or (2) above, wherein the resin (B) is a resin which, is decomposedby the action of an acid to increase solubility in an alkalinedeveloping solution and has at least one repeating unit represented byformulae (IVb), (Vb) and (VIb) as described in item (2) above and atleast one repeating unit represented by the following formulae (VIIb),(VIIIb) and (IXb):

[0044] wherein R_(21b), R_(22b) and R_(24b) to R_(26b), which may be thesame or different, each represents a hydrogen atom, a halogen atom, acyano group, an alkyl group or a haloalkyl group; R_(23b) represents acyano group, —CO—OR_(27b) or —CO—NR_(28b)R_(29b); X_(4b), X_(5b) andX_(6b), which may be the same or different, each represents a singlebond, an optionally substituted divalent alkylene, alkenylene orcycloalkylene group, —O—, —SO₂—, —O—CO—R_(30b)—, —CO—O—R_(31b)— or—CO—NR_(32b)—R_(33b)—; R_(27b) represents a hydrogen atom, an optionallysubstituted alkyl, cycloalkyl or alkenyl group, or a group which isdecomposed by the action of an acid to increase solubility in analkaline developing solution; R_(28b), R_(29b) and R_(32b), which may bethe same or different, each represents a hydrogen atom or an optionallysubstituted alkyl, cycloalkyl or alkenyl group, or R_(28b) and R_(29b)may be bonded to each other to form a ring; R_(30b), R_(31b) andR_(33b), which may be the same or different, each represents a singlebond or a divalent alkylene, alkenylene or cycloalkylene group, or adivalent group formed by combining each of these groups with an ether,ester, amido, urethane or ureido group; and B_(b) is a group which isdecomposed by the action of an acid to increase solubility in analkaline developing solution;

[0045] (4) a positive photosensitive composition as described in any oneof items (1) to (3) above, wherein the resin (B) further comprises acarboxy group;

[0046] (5) a positive photosensitive composition as described in item(4) above, wherein the resin (B) further comprises at least onerepeating unit represented by the following formulae (Xb), (XIb) and(XIIb) each having a carboxy group:

[0047] wherein R_(34b), R_(35b) and R_(37b) to R_(39b), which may be thesame or different, each represents a hydrogen atom, a halogen atom, acyano group, an alkyl group or a haloalkyl group; R_(36b) represents acyano group, a carboxy group, —CO—OR_(40b) or —CO— NR_(41b)R_(42b);X_(7b), X_(8b) and X_(9b), which may be the same or different, eachrepresents a single bond, an optionally substituted divalent alkylene,alkenylene or cycloalkylene group, —O—, —SO₂—, —O—CO—R_(43b)—,—CO—O—R_(44b)— or —CO—NR_(45b)—R_(46b)—; R_(40b) represents anoptionally substituted alkyl, cycloalkyl or alkenyl group; R_(41b),R_(42b) and R_(45b), which may be the same or different, each representsa hydrogen atom or an optionally substituted alkyl, cycloalkyl oralkenyl group, or R_(41b) and R_(42b) may be bonded to each other toform a ring; R_(43b), R_(44b) and R_(46b), which may be the same ordifferent, each represents a single bond or a divalent alkylene,alkenylene or cycloalkylene group, or a divalent group formed bycombining each of these groups with an ether, ester, amido, urethane orureido group;

[0048] (6) a positive photosensitive composition as described in any oneof items (1) to (5) above, wherein the composition further comprises alow molecular weight acid-decomposable dissolution inhibiting compoundwhose solubility in an alkaline developing solution increases by theaction of an acid and which has a group capable of being decomposed bythe action of an acid and a molecular weight of 3,000 or less;

[0049] (7) a positive photosensitive composition as described in any ofitems (1) to (6) above, wherein the composition is suitable for exposureusing far ultraviolet light having a wavelength of 250 nm or less as anexposure light source; and

[0050] (8) a positive photosensitive composition as described in item(7) above, wherein the composition is suitable for exposure using farultraviolet light having a wavelength of 220 nm or less as an exposurelight source.

DETAILED DESCRIPTION OF THE INVENTION

[0051] Now, the first embodiment of the photosensitive compositionaccording to the present invention will be described in more detailbelow.

[0052] Component (B): a resin having a structure represented by formula(I), (II) or (III) described above and a group which is decomposed bythe action of an acid to increase solubility in an alkaline developingsolution (hereinafter also referred to as an acid-decomposable groupsometimes):

[0053] In the present invention, the structure represented by formula(I), (II) or (III) describe above and the acid-decomposable group eachmay be bonded to any site of the base resin. Specifically, the structurerepresented by formula (I), (II) or (III) describe above and theacid-decomposable group may be bonded to different repeating units inthe base resin. Alternatively, the base resin may contain repeatingunits each having both the structure represented by formula (I), (II) or(III) describe above and the acid-decomposable group. Further, thestructure represented by formula (I), (II) or (III) describe above andthe acid-decomposable group are present in the base resin in these twomanners described above. Moreover, the structure represented by formula(I), (II) or (III) describe above may contain the acid-decomposablegroup.

[0054] In the formula (I), (II) or (III) describe above, the optionallysubstituted straight-chain, branched chain or cyclic alkyl grouprepresented by R₁, R₂, R₃, R₄ or R₅ is preferably an optionallysubstituted straight-chain, branched chain or cyclic alkyl group havingfrom 1 to 12 carbon atoms, for example, methyl, ethyl, propyl, n-butyl,sec-butyl, hexyl, 2-ethylhexyl, octyl, cyclopropyl or cyclopentyl.

[0055] R₁ and R₂ may be bonded to each other to form a monocyclic orpolycyclic ring which may contain an oxygen atom, a sulfur atom, anitrogen atom, a ketone bond, an ester bond, an imido bond or an amidobond as a linking group. The ring structure includes a 5-membered to8-membered ring and a polycyclic structure containing two or more5-membered to 8-membered rings. Specific examples thereof includecyclohexane ring, cyclopentane ring, tetrahydropyran ring, piperidinering, retrahydropyrrole ring, cyclohexanone ring and butyrolactone ring.

[0056] The alkoxy group represented by R₃, R₄ or R₅ is preferably anoptionally substituted alkoxy group having from 1 to 8 carbon atoms, forexample, methoxy, ethoxy, hydroxyethoxy, propoxy, hydroxypropoxy orbutoxy.

[0057] Two or more of R₃, R₄ and R₅ may be bonded to each other to forma monocyclic or polycyclic ring which may contain an oxygen atom, asulfur atom, a nitrogen atom, a ketone bond, an ester bond, an imidobond or an amido bond as a linking group. The ring structure includethose described for R₁ and R₂.

[0058] R₁, R₂, R₃, R₄ or R₅ may have a substituent, for example, analkyl group, an alkenyl group, an alkoxy group, an acyloxy group or ahalogen atom.

[0059] X represents a single bond or a divalent linking group. Thedivalent linking group includes, for example, an oxygen atom, a sulfuratom, —NH— and a divalent organic group. The divalent organic groupincludes, for example, an optionally substituted straight-chain,branched chain or cyclic alkylene or alkenylene group, —COO—, —CO—,—SO₂—, —SO₂NH—, —CONH—, —CONHSO₂—, —N(alkyl)—(wherein alkyl preferablyrepresents an alkyl group having from 1 to 8 carbon atoms, for example,methyl, ethyl, propyl, butyl or octyl), —COS—, or a divalent linkinggroup composed of two or more of these groups.

[0060] The alkylene group included in X is preferably an optionallysubstituted alkylene group having from 1 to 8 carbon atoms, for example,methylene, ethylene, propylene, butylene, hexylene or octylene. Thecyclic alkylene group included in X is preferably an optionallysubstituted cyclo alkylene group having from 5 to 8 carbon atoms, forexample, cyclopenthylene or cyclohexylene. The alkenylene group includedin X is preferably an optionally substituted alkenylene group havingfrom 2 to 6 carbon atoms, for example, ethenylene, propenylene orbutenylene.

[0061] Y represents an oxygen atom, a sulfur atom, —NH—, —N(OH)— or—N(alkyl)—(wherein alkyl preferably represents an alkyl group havingfrom 1 to 8 carbon atoms, for example, methyl, ethyl, propyl, butyl oroctyl). An oxygen atom or a sulfur atom is preferred.

[0062] n represents an integer of from 1 to 3.

[0063] In the resin according to the present invention, although arepeating structural unit having the group represented by any one offormulae (I) to (III) may be any unit having the group represented byone of formulae (I) to (III), a repeating structural unit represented byany one of the following formulae (IV) to (VI) is preferred. Amongothers, the repeating structural unit represented by formula (IV) ismore preferred.

[0064] wherein R₁₅, R₁₆ and R₁₈ to R₂₀, which may be the same ordifferent, each represents a hydrogen atom, a halogen atom, a cyanogroup, an alkyl group or a haloalkyl group; R₁₇ represents a cyanogroup, —CO—OR₂₇ or —CO—NR₂₈R₂₉; X₁, X₂ and X₃, which may be the same ordifferent, each represents a single bond, an optionally substituteddivalent alkylene, alkylene or cycloalkylene group, —CO—, —SO₂—,—O—CO—R₃₀—, —CO—O—R₃₁— or —CO—NR₃₂—R₃₃—; R₂₇ represents a hydrogen atom,an optionally substituted alkyl, cycloalkyl or alkenyl group, or a groupwhich is decomposed by the action of an acid to increase solubility inan alkaline developing solution; R₂₈, R₂₉ and R₃₂, which may be the sameor different, each represents a hydrogen atom or an optionallysubstituted alkyl, cycloalkyl or alkenyl group, or R₂₈ and R₂₉ may bebonded to each other to form a ring; R₃₀, R₃₁ and R₃₃, which may be thesame or different, each represents a single bond or a divalent alkylene,alkenylene or cycloalkylene group, or a divalent group formed bycombining each of these groups with an ether, ester, amido, urethane orureido group; and Y represents the structure represented by formula (I),(II) or (III) described above.

[0065] Preferred examples of the alkyl group represented by each of R₂₇to R₂₉ and R₃₂ include an optionally substituted alkyl group having from1 to 8 carbon atoms, such as methyl, ethyl, propyl, n-butyl, sec-butyl,hexyl, 2-ethylhexyl, and octyl.

[0066] Preferred examples of the cycloalkyl group represented by each ofR₂₇ to R₂₉ and R₃₂ include an optionally substituted cycloalkyl groupsuch having from 3 to 8 carbon atoms, such as cyclopropyl, cyclopentyl,and cyclohexyl.

[0067] Preferred examples of the alkenyl group represented by each ofR₂₇ to R₂₉ and R₃₂ include an optionally substituted alkenyl grouphaving from 2 to 6 carbon atoms, such as vinyl, propenyl, allyl,butenyl, pentenyl, hexenyl, and cyclohexenyl.

[0068] In the structure represented by formula (I), (II) or (III), thelinking group represented by X may be bonded to the cyclic structure inany position thereof.

[0069] Preferred examples of the alkyl group represented by each of R₁₅,R₁₆ and R₁₈ to R₂₀ include an optionally substituted alkyl group havingfrom 1 to 4 carbon atoms, such as methyl, ethyl, propyl, n-butyl, andsec-butyl.

[0070] Preferred examples of the haloalkyl group represented by each ofR₁₅, R₁₆ and R₁₈ to R₂₀ include an alkyl group having from 1 to 4 carbonatoms and substituted with one or more of fluorine, chlorine, andbromine atoms. Specific examples thereof include fluoromethyl,chloromethyl, bromomethyl, fluoroethyl, chloroethyl, and bromoethyl.

[0071] Preferred examples of the alkylene group represented by each ofX₁, X₂ and X₃ include an optionally substituted alkylene group havingfrom 1 to 8 carbon atoms, such as methylene, ethylene, propylene,butylene, hexylene, and octylene.

[0072] Preferred examples of the alkenylene group represented by each ofX₁, X₂ and X₃ include an optionally substituted alkenylene group havingfrom 2 to 6 carbon atoms, such as ethenylene, propenylene, andbutenylene.

[0073] Preferred examples of the cycloalkylene group represented by eachof X₁, X₂ and X₃ include an optionally substituted cycloalkylene grouphaving from 5 to 8 carbon atoms, such as cyclopentylene andcyclohexylene.

[0074] Examples of the alkylene, alkenylene and cycloalkylene groupsrepresented by each of R₃₀, R₃₁ and R₃₃ include the same alkylene,alkenylene and cycloalkylene groups as those described above, andfurther include divalent groups each formed by combining any one ofthose groups with at least one of ether, ester, amido, urethane andureido groups.

[0075] Preferred examples of the ring formed by bonding R₂₈ and R₂₉ eachother together with the nitrogen atom include five- to eight-memberedrings. Specific examples thereof include pyrrolidine, piperidine, andpiperazine.

[0076] R₂₇ also represents a group which is decomposed by the action ofan acid to increase solubility in an alkaline developing solution(acid-decomposable group).

[0077] In the resin according to the present invention, theacid-decomposable group may be contained in the structure of grouprepresented by one of formulae (I) to (III) or may be contained in arepeating unit having a group represented by any one of formulae (I) to(III) (for example, as R₂₇), or may be contained in other repeatingunits. The acid-decomposable groups may be contained in two or morekinds of such structures or units.

[0078] Examples of the acid-decomposable group include a group which ishydrolyzed by the action of an acid to form an acid and a group whichreleases a carbon cation by the action of an acid to form an acid.Preferred examples thereof include groups represented by the followingformulae (XIII) and (XIV). Such acid-decomposable groups serve to impartexcellent storage stability.

[0079] wherein R₄₇ to R₄₉, which may be the same or different, eachrepresents a hydrogen atom or an optionally substituted alkyl,cycloalkyl or alkenyl group, provided that at least one of R₄₇ to R₄₉ informula (XIII) is not a hydrogen atom; R₅₀ represents an optionallysubstituted alkyl, cycloalkyl, or alkenyl group; or two of R₄₇ to R₄₉ informula (XIII) or two of R₄₇, R₄₈ and R₅₀ in formula (XIV) may be bondedto each other to form a three- to eight-membered cyclic structurecomprising carbon atoms and optionally containing one or moreheteroatoms; and Z₁ and Z₂, which may be the same or different, eachrepresents an oxygen atom or a sulfur atom.

[0080] Specific examples of the cyclic structure include cyclopropyl,cyclopentyl, cyclohexyl, cycloheptyl, 1-cyclohexenyl,2-tetrahydrofuranyl and 2-tetrahydropyranyl.

[0081] Preferred examples of the alkyl, cycloalkyl and alkenyl groupsare the same as those described hereinabove with regard to R₂₇.

[0082] Preferred examples of the substituent which may be possessed bythe substituents described above in detail include a hydroxy group, ahalogen atom (fluorine, chlorine, bromine and iodine), a nitro group, acyano group, an amido group, a sulfonamido group, an alkyl group asdescribed for R₂₇ above, an alkoxy group such as methoxy, ethoxy,hydroxyethoxy, propoxy, hydroxypropoxy and butoxy, an alkoxycarbonylgroup such as methoxycarbonyl and ethoxycarbonyl, an acyl group such asformyl, acetyl and benzoyl, an acyloxy group such as acetoxy andbutyryloxy, and a carboxy group.

[0083] The content of repeating unit having the alicyclic grouprepresented by formula (I), (II) or (III) (preferably a repeating unitrepresented by any one of formulae (IV) to (VI)) in the resin accordingto the present invention may be controlled while taking account of thebalance among the dry etching resistance, developing property withalkali and the like. However, the content thereof is preferably 20% bymole or more, more preferably from 30 to 80% by mole, yet morepreferably from 40 to 70% by mole, based on the total repeating units.

[0084] Specific examples of the repeating unit represented by any one offormulae (IV) to (VI) are set forth below as (a1) to (a50). However, thepresent invention should not be construed as being limited thereto.

[0085] Of the repeating structural units according to the presentinvention, those having the following structure which includes atertiary ester group as a connecting group are excellent in theacid-decomposability and particularly preferred in view of sensitivity.

[0086] wherein R₁ to R₅, Y, n and R₁₅ each has the same meaning asdefined above.

[0087] The resin having the structure represented by formula (a) whereinthe ester linking group is bound to the lactone exhibits a highhydrophilic properties due to the synergic effect of adjacent oxygenatoms and is preferred in terms of sensitivity, adhesion to substrate,and reduction of development defects. Furthermore, the resin having thestructure represented by formula (b) wherein the ester linking group isbound to the α-position of the lactone is preferred in terms ofsensitivity, adhesion to substrate, reduction of development defects,and resolution, since the lactone decomposes with an alkali developingsolution to produce carboxylic acid, so that the dissolution rate of theexposed portion increases.

[0088] Component (C): a low molecular weight compound having a molecularweight of 3,000 or less and having a group which is decomposed by theaction of an acid to increase solubility in an alkaline developingsolution:

[0089] The acid-decomposable dissolution inhibiting compound for use inthe present invention is a low molecular weight compound which containsat least one structure represented by formula (I), (II) or (III), has amolecular weight of 3,000 or less and may further contain anacid-decomposable group, when it is employed in combination with analkaline-soluble resin. On the other hand, when the compound is used incombination with the resin according to the present invention, it is acompound which contains an acid-decomposable group, may or may notcontain the group represented by any one of formulae (I) to (III), andhas a molecular weight of 3,000 or less.

[0090] In order to prevent reduction in transmissibility particularly at220 nm or less, an alicyclic or aliphatic compound such as a cholic acidderivative described in Proceeding of SPIE, 2724, 355 (1996) ispreferred. In the present invention, when the acid-decomposabledissolution inhibiting compound is used, the amount thereof added isfrom 3 to 50% by weight, preferably from 5 to 40% by weight, morepreferably form 10 to 35% by weight, based on the whole solid content ofthe photosensitive composition.

[0091] Specific examples of the low molecular weight compound having amolecular weight of 3,000 or less and containing the group representedby any one of formulae (I) to (III) and a group which is decomposed bythe action of an acid to increase solubility in an alkaline developingsolution are set forth below, but the present invention should not beconstrued as being limited thereto.

[0092] Component (D): a resin which has a group that is decomposed bythe action of an acid to increase solubility in an alkaline developingsolution and contains at least one repeating unit having a structurerepresented by formula (I), (II) or (III) described above and arepeating unit having a monoalicyclic or polyalicyclic hydrocarbonmoiety:

[0093] The objects of the present invention can be attained by using theresin which contains at least one repeating unit having a structurerepresented by formula (I), (II) or (III) described above and arepeating unit having a monoalicyclic or polyalicyclic hydrocarbonmoiety as the resin having a group which is decomposed by the action ofan acid to increase solubility in an alkaline developing solution inorder to increase dry etching resistance.

[0094] The structural unit having the monoalicyclic or polyalicyclichydrocarbon moiety used in resin (D) is preferably selected fromstructural units having an alicyclic group, represented by the followingformula (VII), (VIII) or (IX):

[0095] wherein R₃₅, R₃₆ and R₃₈ to R₄₀, which may be the same ordifferent, each represents a hydrogen atom, a halogen atom, a cyanogroup, an alkyl group or a haloalkyl group; R₃₇ represents a cyanogroup, —CO—OR₄₇ or —CO—NR₄₈R₄₉; X₄, X₅ and X₆, which may be the same ordifferent, each represents a single bond, an optionally substituteddivalent alkylene, alkenylene or cycloalkylene group, —CO—, —SO₂—,—O—CO—R₅₀—, —CO—O—R₅₁— or —CO—NR₅₂—R₅₃—; R₄₇ represents a hydrogen atom,an optionally substituted alkyl, cycloalkyl or alkenyl group, or a groupwhich is decomposed by the action of an acid to increase solubility inan alkaline developing solution; R₄₈, R₄₉ and R₅₂, which may be the sameor different, each represents a hydrogen atom or an optionallysubstituted alkyl, cycloalkyl or alkenyl group, or R₄₈ and R₄₉ may bebonded to each other to form a ring; R₅₀, R₅₁ and R₅₃, which may be thesame or different, each represents a single bond or a divalent alkylene,alkenylene or cycloalkylene group, or a divalent group formed bycombining each of these groups with an ether, ester, amido, urethane orureido group; and A represents a monoalicyclic or polyalicylic group.

[0096] Details of the substituents represented by R₃₅ to R₄₀, R₄₇ to R₅₃and X₄ to X₆ are same as those described for R₁₅ to R₂₀, R₂₇ to R₃₃ andX₁ to X₃ in formulae (IV) to (VI) above, respectively. Preferredexamples thereof are also same as those described above.

[0097] The monoalicyclic group represented by A includes an optionallysubstituted monoalicyclic group having 3 or more carbon atoms, forexample, cyclopropane, cyclobutane, cyclopentane or cyclohexane,preferably an optionally substituted monoalicyclic group having from 3to 8 carbon atoms.

[0098] The polyalicyclic group represented by A includes an optionallysubstituted polyalicyclic group having 5 or more carbon atoms, forexample, bicyclo-, tricyclo- or tetra-cyclo-alicyclic group, preferablyan optionally substituted polyalicyclic group having from 6 to 30 carbonatoms, more preferably an optionally substituted polyalicyclic grouphaving from 7 to 25 carbon atoms.

[0099] Preferred examples of the substituent of the polyalicyclic groupinclude a hydroxyl group, a halogen atom (e.g., fluorine, chlorine,bromine or iodine), a nitro group, a cyano group, an amido group, asulfonamido group, an alkyl group such as the alkyl group described forR₄₇ above, an alkoxy group having from 1 to 8 carbon atoms, for example,methoxy, ethoxy, hydroxyethoxy, propoxy, hydroxy-propoxy or butoxy, analkoxycarbonyl group, for example, methoxycarbonyl or ethoxycarbonyl, anacyl group, for example, formyl, acetyl or benzoyl, an acyloxy group,for example, acetoxy or butyryloxy, and a carboxy group.

[0100] Representative structural examples of the polyalicyclic ormonoalicyclic moiety in the polyalicyclic or monoalicyclic group are setforth below.

[0101] The content of the structural unit having the alicyclic groupdescribed above (preferably the repeating unit represented by formula(VII), (VIII) or (IX)) in the resin according to the present inventionis controlled while taking account of the balance among dry etchingresistance, developing property with alkali and the like. However, thecontent thereof is preferably 20% by mole or more, more preferably from30 to 80% by mole, still more preferably from 35 to 70% by mole, andparticularly preferably from 40 to 60% by mole, based on the wholerepeating unit.

[0102] In resin (D), a ratio of the repeating unit having the structurerepresented by formula (I), (II) or (III) to the repeating unitcontaining a monoalicyclic or polyalicyclic hydrocarbon moiety ispreferably from 80:20 to 20:80, more preferably from 70:30 to 30:70.Also, the monoalicyclic or polyalicyclic hydrocarbon moiety may beincluded in the repeating unit having the structure represented byformula (I), (II) or (III).

[0103] Specific examples of the repeating unit represented by any one offormulae (VII), (VIII) and (IX) are set forth below, but the presentinvention should not be construed as being limited thereto.

[0104] Component (E): a resin which is insoluble in water but soluble inan alkaline developing solution:

[0105] A resin which is insoluble in water but soluble in an alkalinedeveloping solution and does not contain an acid-decomposable group(hereinafter simply referred to as an alkali-soluble resin sometimes)can be employed in the positive photosensitive composition according tothe present invention in order to increase sensitivity. Thealkali-soluble resin containing no acid-decomposable group describedabove preferably includes a resin containing a repeating unit having acarboxy group (preferably a repeating unit represented by formula (XV),(XVI) or (XVII) shown hereinafter). One or more other monomers asdescribed in <Other polymerizable monomers> described hereinafter may becopolymerized therewith in order to control alkali-solubility. Also, inorder to improve dry etching resistance, a repeating unit having analicyclic group represented by formula (VII), (VIII) or (IX) describedabove may be copolymerized therewith. Further, both of thesecopolymerization described above may be effected.

[0106] In the present invention, novolak resins or polyhydroxy styrenederivatives may also be employed. However, since these resins have largeabsorption to light having a wavelength of 250 nm or shorter, it ispreferred to use them in the partially hydrogenated form or in an amountof not more than 30% by weight based on the whole amount of resin.

[0107] The alkali-soluble resin containing an acid-decomposable groupwhich can be contained in the positive photosensitive composition maycomprise at least one repeating unit represented by the followingformulae (X), (XI) and (XII):

[0108] wherein R₅₅, R₅₆ and R₅₈ to R₆₀, which may be the same ordifferent, each represents a hydrogen atom, a halogen atom, a cyanogroup, an alkyl group or a haloalkyl group; R₅₇ represents a cyanogroup, —CO—OR₆₇ or —CO—NR₆₈R₆₉; X₇, X₈ and X₉, which may be the same ordifferent, each represents a single bond, an optionally substituteddivalent alkylene, alkenylene or cycloalkylene group, —CO—, —SO₂—,—O—CO—R₇₀—, —CO—O—R₇₁— or —CO—NR₇₂—R₇₃—; R₆₇ represents a hydrogen atom,an optionally substituted alkyl, cycloalkyl or alkenyl group, or a groupwhich is decomposed by the action of an acid to increase solubility inan alkaline developing solution; R_(68,) R₆₉ and R₇₂, which may be thesame or different, each represents a hydrogen atom or an optionallysubstituted alkyl, cycloalkyl or alkenyl group, or R₆₈ and R₆₉ may bebonded to each other to form a ring; R₇₀, R₇₁ and R₇₃, which may be thesame or different, each represents a single bond or a divalent alkylene,alkenylene or cycloalkylene group, or a divalent group formed bycombining each of these groups with an ether, ester, amido, urethane orureido group; and B is a group which is decomposed by the action of anacid to increase solubility in an alkaline developing solution.

[0109] Details of the group which is decomposed by the action of an acidto increase solubility in an alkaline developing solution represented byB are same as those of the acid-decomposable group described for R₂₇ informula (IV), (V) or (VI) above.

[0110] Details of the substituents represented by R₅₅ to R₆₀, R₆₇ to R₇₃and X₇ to X₉ are same as those described for R₁₅ to R₂₀, R₂₇ to R₃₃ andX₁ to X₃ in formulae (IV) to (VI) above, respectively. Preferredexamples thereof are also same as those described above.

[0111] The content of the repeating unit represented by formula (X),(XI) or (XII) in the resin according to the present invention iscontrolled while taking account of characteristics such as developingproperty with alkali, adhesion to a substrate and the like. However, thecontent thereof is preferably from 0 to 80% by mole, more preferablyfrom 0 to 70% by mole, and still more preferably from 0 to 60% by mole,based on the whole repeating unit.

[0112] Specific examples of the repeating unit represented by any one offormulae (X), (XI) and (XII) are set forth below, but the presentinvention should not be construed as being limited thereto.

[0113] The resin according to the present invention may further containa carboxy group.

[0114] The carboxy group may be contained in the repeating unitrepresented by any one of formulae (IV) to (IX) described above, or maybe contained in the repeating unit having the acid-decomposable groupand the low molecular weight compound (C), or may be contained in arepeating unit other than those repeating units. Further, the carboxygroups may be contained in two or more kinds of such positions asdescribed above.

[0115] A repeating unit having the carboxy group is preferably arepeating unit represented by the following formula (XV), (XVI) or(XVII):

[0116] wherein R₇₅, R₇₆ and R₇₈ to R₈₀, which may be the same ordifferent, each represents a hydrogen atom, a halogen atom, a cyanogroup, an alkyl group or a haloalkyl group; R₇₇ represents a cyanogroup, —CO—OR₈₇ or —CO—NR₈₈R₈₉; X₁₀, X₁₁, and X₁₂, which may be the sameor different, each represents a single bond, an optionally substituteddivalent alkylene, alkenylene or cycloalkylene group, —CO—, —SO₂—,—O—CO—R₉₀—, —CO—O—R₉₁— or —CO—NR₉₂—R₉₃—; R₈₇ represents a hydrogen atom,an optionally substituted alkyl, cycloalkyl or alkenyl group, or a groupwhich is decomposed by the action of an acid to increase solubility inan alkaline developing solution; R₈₈, R₈₉ and R₉₂, which may be the sameor different, each represents a hydrogen atom or an optionallysubstituted alkyl, cycloalkyl or alkenyl group, or R₈₈ and R₈₉ may bebonded to each other to form a ring; and R₉₀, R₉₁ and R₉₃, which may bethe same or different, each represents a single bond or a divalentalkylene, alkenylene or cycloalkylene group, or a divalent group formedby combining each of these groups with an ether, ester, amido, urethaneor ureido group.

[0117] Details of the substituents represented by R₇₅ to R₈₀, R₈₇ to R₉₃and X₁₀ to X₁₂ are same as those described for R₁₅ to R₂₀, R₂₇ to R₃₃and X₁ to X₃ in formulae (IV) to (VI) above, respectively. Preferredexamples thereof are also same as those described above.

[0118] The content of the repeating unit having a carboxy groupdescribed above (preferably the repeating unit represented by formula(XV), (XVI) or (XVII)) in the resin according to the present inventionis controlled while taking account of characteristics such as developingproperty with alkali, adhesion to a substrate, sensitivity and the like.However, the content thereof is preferably from 0 to 60% by mole, morepreferably from 0 to 40% by mole, and still more preferably from 0 to20% by mole, based on the whole repeating unit. The content of carboxygroup-containing repeating unit used herein means a content of the totalcarboxy group-containing repeating units in the resin, including therepeating unit having a carboxy group represented by any one of formulae(IV) to (IX), the low molecular weight compound (C) and the repeatingunit containing an acid-decomposable group and a carboxy group.

[0119] Specific examples of the repeating unit represented by any one offormulae (XV), (XVI) and (XVII) are set forth below, but the presentinvention should not be construed as being limited thereto.

[0120] Other Polymerizable Monomers

[0121] For the purpose of improving characteristics of the resin for usein the first embodiment of the photosensitive composition according tothe present invention, one or more other monomers may further becopolymerized within the range of not severely impairingtransmissibility at 220 nm or less and dry etching resistance of theresin.

[0122] Examples of the copolymerizable monomer which can be used includecompounds having one addition-polymerizable unsaturated bond, selected,for example, from acrylic acid esters, acrylamides, methacrylic acidesters, methacrylamides, allyl compounds, vinyl ethers, vinyl esters,styrenes and crotonic acid esters.

[0123] Specific examples thereof include acrylic acid esters such asalkyl (the alkyl group preferably has from 1 to 10 carbon atoms)acrylate (e.g., methyl acrylate, ethyl acrylate, propyl acrylate,tert-butyl acrylate, amyl acrylate, cyclohexyl acrylate, ethylhexylacrylate, octyl acrylate, tert-octyl acrylate, chloroethyl acrylate,2-hydroxyethyl acrylate, 2,2-dimethylhydroxypropyl acrylate,5-hydroxypentyl acrylate, trimethylolpropane monoacrylate,pentaerythritol monoacrylate, glycidyl acrylate, benzyl acrylate,methoxybenzyl acrylate, furfuryl acrylate, or tetrahydrofurfurylacrylate) and aryl acrylate (e.g., phenyl acrylate, or hydroxyphenylacrylate); methacrylic acid esters such as alkyl (the alkyl grouppreferably has from 1 to 10 carbon atoms) methacrylate (e.g., methylmethacrylate, ethyl methacrylate, propyl methacrylate, isopropylmethacrylate, tert-butyl methacrylate, amyl methacrylate, hexylmethacrylate, cyclohexyl methacrylate, benzyl methacrylate, chlorobenzylmethacrylate, octyl methacrylate, 2-hydroxyethyl methacrylate,4-hydroxybutyl methacrylate, 5-hydroxypentyl methacrylate,2,2-dimethyl-3-hydroxypropyl methacrylate, trimethylolpropanemono-methacrylate, pentaerythritol monomethacrylate, glycidylmethacrylate, furfuryl methacrylate, or tetrahydrofurfuryl methacrylate)and aryl methacrylate (e.g., phenyl methacrylate, hydroxyphenylmethacrylate, cresyl methacrylate, or naphthyl methacrylate);acrylamides such as acrylamide, N-alkylacrylamide (the alkyl group is analkyl group having from 1 to 10 carbon atoms, for example, methyl group,ethyl group, propyl group, butyl group, tert-butyl group, heptyl group,octyl group, cyclohexyl group, benzyl group, hydroxyethyl group orbenzyl group), N-arylacrylamide (the aryl group is, for example, phenylgroup, tolyl group, nitrophenyl group, naphthyl group, cyanophenylgroup, hydroxyphenyl group or carboxyphenyl group),N,N-dialkylacrylamide (the alkyl group is an alkyl group having from 1to 10 carbon atoms, for example, methyl group, ethyl group, butyl group,isobutyl group, ethylhexyl group or cyclohexyl group),N,N-diarylacrylamide (the aryl group is, for example, phenyl group),N-methyl-N-phenylacrylamide, N-hydroxyethyl-N-methylacrylamide andN-2-acetamidoethyl-N-acetylacrylamide; methacrylamides such asmethacrylamide, N-alkylmethacrylamide (the alkyl group is an alkyl grouphaving from 1 to 10 carbon atoms, for example, methyl group, ethylgroup, tert-butyl group, ethylhexyl group, hydroxyethyl group orcyclohexyl group), N-arylmethacrylamide (the aryl group is, for example,phenyl group, hydroxyphenyl group or carboxyphenyl group),N,N-dialkylmethacrylamide (the alkyl group is, for example, ethyl group,propyl group or butyl group), N,N-diaryl-methacrylamide (the aryl groupis, for example, phenyl group), N-hydroxyethyl-N-methylmethacrylamide,N-methyl-N-phenylmethacrylamide and N-ethyl-N-phenylmethacrylamide;allyl compounds such as allyl esters (e.g., allyl acetate, allylcaproate, allyl caprylate, allyl laurate, allyl palmitate, allylstearate, allyl benzoate, allyl acetoacetate, or allyl lactate) andallyloxyethanol; vinyl ethers such as alkyl vinyl ether (e.g., hexylvinyl ether, octyl vinyl ether, decyl vinyl ether, ethylhexyl vinylether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, chloroethylvinyl ether, 1-methyl-2,2-dimethylpropyl vinyl ether, 2-ethylbutyl vinylether, hydroxyethyl vinyl ether, diethylene glycol vinyl ether,dimethylaminoethyl vinyl ether, diethylaminoethyl vinyl ether,butylaminoethyl vinyl ether, benzyl vinyl ether, or tetrahydrofurfurylvinyl ether) and vinyl aryl ether (e.g., vinyl phenyl ether, vinyl tolylether, vinyl chlorophenyl ether, vinyl 2,4-dichlorophenyl ether, vinylnaphthyl ether, vinyl anthranyl ether); vinyl esters such as vinylbutyrate, vinyl isobutyrate, vinyl trimethyl acetate, vinyl diethylacetate, vinyl valerate, vinyl caproate, vinyl chloroacetate, vinyldichloroacetate, vinyl methoxy acetate, vinyl butoxy acetate, vinylphenyl acetate, vinyl acetoacetate, vinyl lactate, vinyl-β-phenylbutyrate, vinylcyclohexyl carboxylate, vinyl benzoate, vinyl salicylate,vinyl chlorobenzoate, vinyl tetrachlorobenzoate and vinyl naphthoate;styrenes such as styrene, alkylstyrene (e.g., methylstyrene,dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene,isopropylstyrene, butylstyrene, hexylstyrene, cyclohexylstyrene,decylstyrene, benzylstyrene, chloromethylstyrene,trifluoromethylstyrene, ethoxymethylstyrene, or acetoxymethylstyrene),alkoxystyrene (e.g., methoxystyrene, 4-methoxy-3-methylstyrene, ordimethoxystyrene), halostyrene (e.g., chlorostyrene, dichlorostyrene,trichlorostyrene, tetrachlorostyrene, pentachlorostyrene, bromostyrene,dibromostyrene, iodostyrene, fluorostyrene, trifluorostyrene,2-bromo-4-trifluoromethylstyrene, or 4-fluoro-3-trifluoromethylstyrene),hydroxystyrene (e.g., 4-hydroxystyrene, 3-hydroxystyrene,2-hydroxystyrene, 4-hydroxy-3-methylstyrene,4-hydroxy-3,5-dimethylstyrene, 4-hydroxy-3-methoxystyrene, or4-hydroxy-3-(2-hydroxybenzyl)styrene) and carboxystyrene; crotonic acidesters such as alkyl crotonate (e.g., butyl crotonate, hexyl crotonate,or glycerin monocrotonate); dialkyl itaconates (e.g., dimethylitaconate, diethyl itaconate, or dibutyl itaconate); dialkyl esters of amaleic acid or fumaric acid (e.g., dimethyl maleate, or dibutylfumarate); maleic anhydride; maleimide; acrylonitrile;methacrylonitrile; and maleonitrile. In addition, addition-polymerizableunsaturated compounds which can be copolymerized in general may be used.

[0124] Among these, monomers capable of increasing the alkalisolubility, for example, monomers having a carboxyl group, such ascarboxystyrene, N-(carboxyphenyl)acrylamide andN-(carboxyphenyl)methacrylamide, monomers having a phenolic hydroxylgroup, such as hydroxystyrene, N-(hydroxyphenyl)-acrylamide,N-(hydroxyphenyl)methacrylamide, hydroxyphenyl acrylate and hydrophenylmethacrylate, and maleimide are preferred as the copolymerizablecomponent.

[0125] The content of the other polymerizable monomer in the resinaccording to the present invention is preferably not more than 50% bymole, more preferably not more than 30% by mole, based on the wholerepeating unit.

[0126] The resin according to the present invention which contains therepeating unit having the structural group represented by formula (I),(II) or (III) (preferably the repeating unit represented by any one offormulae (IV) to (IX)), the repeating unit having an acid-decomposablegroup (preferably the repeating unit represented by any one of formulae(X) to (XII)), if desired, the repeating unit having a carboxy group(preferably the repeating unit represented by any one of formulae (XV)to (XVII)), if desired, and a repeating unit derived from otherpolymerizable monomer, if desired, is synthesized by a radical, cationor anion polymerization of unsaturated monomers corresponding to therespective structures.

[0127] More specifically, the respective monomers are mixed based on thedesired composition as described above and polymerized in an appropriatesolvent in a monomer concentration of from about 10 to 40% by weight byadding a polymerization catalyst, and if desired, by heating.

[0128] The resin according to the present invention has a molecularweight, in terms of a weight average molecular weight (Mw: polystyrenebasis), of 2,000 or more, preferably from 3,000 to 1,000,000, morepreferably from 3,000 to 200,000, and still more preferably from 4,000to 100,000. As the molecular weight is larger, heat resistance or thelike is more improved, however, developing property or the likedeteriorates. Therefore, the molecular weight is controlled in apreferred range taking account of the balance of these characteristics.A degree of dispersion (Mw/Mn) is preferably from 1.0 to 5.0, morepreferably from 1.0 to 3.0. As the degree of dispersion is smaller, heatresistance and image performance (pattern profile, defocus latitude, orthe like) are improved.

[0129] In the present invention, the amount of the above described resinadded to the photosensitive composition is from 50 to 99.7% by weight,preferably from 70 to 99% by weight, based on the whole solid content.

[0130] Component (F): a fluorine-base and/or silicon-base surface activeagent:

[0131] The fluorine-base surface active agent and silicon-base surfaceactive agent which can be included in the positive photosensitivecomposition according to the present invention is described below.

[0132] The photosensitive composition according to the present inventionmay contain either a fluorine-base surface active agent, a silicon-basesurface active agent or both of them.

[0133] Examples of the surface active agents (F) include those describedin JP-A-62-36663, JP-A-61-226746, JP-A-61-226745, JP-A-62-170950,JP-A-63-34540, JP-A-7-230165, JP-A-8-62834, JP-A-9-54432 andJP-A-9-5988, U.S. Pat. Nos. 5,405,720, 5,360,692, 5,529,881, 5,296,330,5,436,098, 5,576,143, 5,294,511, and 5,824,451. Commercially availablesurface active agents are also employed as they are.

[0134] Examples of commercially available surface active agents whichcan be used include fluorine-base surface active agents and silicon-basesurface active agents, for example, F-Top EF301 and EF303 (manufacturedby Shin Akita Chemical Co., Ltd.), Florad FC430 and FC431 (manufacturedby Sumitomo 3M Ltd.), Megafac F171, F173, F176, F189 and R₀₈(manufactured by Dainippon Ink and Chemicals, Inc.) and Surflon S-382,SC101, SC102, SC103, SC104, SC105 and SC106 (manufactured by Asahi GlassCo., Ltd.). Also, polysiloxane polymer KP-341 (manufactured by Shin-EtsuChemical Co., Ltd.) is employed as the silicon-base surface activeagent.

[0135] The amount of the surface active agent added is ordinarily from0.01 to 2 parts by weight, preferably from 0.01 to 1 part by weight, per100 parts by weight of the solid content in the photosensitivecomposition according to the present invention.

[0136] The surface active agents may be used individually or incombination of two or more thereof.

[0137] Now, the second embodiment of the photosensitive compositionaccording to the present invention will be described in more detailbelow.

[0138] Component (B): a resin having a polyalicyclic group representedby formula (Ib) described above and a group which is decomposed by theaction of an acid to increase solubility in an alkaline developingsolution (hereinafter also referred to as an acid-decomposable groupsometimes):

[0139] In the present invention, the polyalicyclic group represented byformula (Ib) describe above and the acid-decomposable group each may bebonded to any site of the base resin. Specifically, the polyalicyclicgroup represented by formula (Ib) describe above and theacid-decomposable group may be bonded to different repeating units inthe base resin, or both of them may be bonded to the same repeating unitin the base resin. Further, the polyalicyclic group and theacid-decomposable group are present in the base resin in these twomanners described above.

[0140] In the resin according to the present invention, although arepeating structural unit having the group represented by formula (Ib)may be any unit having the group represented by formula (Ib), arepeating unit represented by any one of formulae (IVb), (Vb) and (VIb)described above is preferred.

[0141] In the above formulae, the alkyl group represented by any one ofR_(a), R_(b), R_(c), R_(d), R_(e), R_(f), R_(g), R_(7b), R_(9b),R_(11b), R_(12b), R_(14b), R_(27b) to R_(29b) and R_(32b) is preferablyan optionally substituted alkyl group having from 1 to 8 carbon atoms,for example, methyl, ethyl, propyl, n-butyl, sec-butyl, hexyl,2-ethylhexyl or octyl. The cycloalkyl group is preferably an optionallysubstituted cycloalkyl group having from 3 to 8 carbon atoms, forexample, cyclopropyl, cyclopentyl or cyclohexyl. The alkenyl group ispreferably an optionally substituted alkenyl group having from 2 to 6carbon atoms, for example, vinyl, propenyl, allyl, butenyl, pentenyl,hexenyl or cyclohexenyl. The alkynyl group represented by any one ofR_(a) to R_(g) is preferably an alkynyl group having from 2 to 4 carbonatoms, for example, acetylene or propargyl.

[0142] Two of R_(a) to R_(g), which are present on the same carbon atom,may represent in combination a carbonyl group (═O) or a thiocarbonylgroup (═S).

[0143] Two of R_(a) to R_(g), which are bonded to adjacent carbon atoms,may be bonded to each other to form a double bond between these twocarbon atoms. It is preferred that the double bond formed between twocarbon atoms is not form a conjugated double bond between two carbonatoms.

[0144] Further, at least two of R_(a) to R_(g) may be bonded to eachother to form a ring. The ring is preferably a 3-membered to 8-memberedring which may contain a hetero atom, for example, cyclopropyl,cyclopentyl, cyclohexyl, cycloheptyl, tetrahydrofuryl ortetrahydropyranyl. The ring may further have a substituent.

[0145] The monovalent polyalicyclic group represented by formula (Ib)may be connected to the resin moiety in any position thereof.

[0146] The polyalicyclic group represented by formula (Ib) describedabove has several stereoisomers and all of such stereoisomers areincluded in the present invention.

[0147] The alkyl group represented by any one of R_(15b), R_(16b),R_(18b) to R_(22b) and R_(24b) to R_(26b) is preferably an optionallysubstituted alkyl group having from 1 to 4 carbon atoms, for example,methyl, ethyl, propyl, n-butyl or sec-butyl. The haloalkyl group ispreferably an alkyl group having from 1 to 4 carbon atoms substitutedwith a fluorine atom, a chlorine atom or a bromine atom, for example,fluoromethyl; chloromethyl, bromomethyl, fluoroethyl, chloroethyl orbromoethyl.

[0148] The alkylene group represented by any one of R_(6b), R_(8b),R_(10b), R_(13b) and X_(1b) to X_(6b) is preferably an optionallysubstituted alkylene group having from 1 to 8 carbon atoms, for example,methylene, ethylene, propylene, butylene, hexylene or octylene.

[0149] The alkenylene group is preferably an optionally substitutedalkenylene group having from 2 to 6 carbon atoms, for example,ethenylene, propenylene or butenylene. The cycloalkylene group ispreferably an optionally substituted cycloalkylene group having from 5to 8 carbon atoms, for example, cyclopentylene or cyclohexylene.

[0150] The alkylene, alkenylene or cycloalkylene group represented byR_(30b), R_(31b) and R_(33b) are same as those described above. R_(30b),R_(31b) and R_(33b) also represents a divalent group formed by combiningeach of these groups with an ether, ester, amido, urethane or ureidogroup.

[0151] The ring formed by R_(11b) and R_(12b) or R_(28b) and R_(29b)together with the nitrogen atom is preferably a 5-membered to 8-memberedring. Specific examples thereof include pyrrolidine, piperidine orpiperazine.

[0152] R_(7b), R_(9b), R_(27b) and B_(b) each represents a group whichis decomposed by the action of an acid to increase solubility in analkaline developing solution (acid-decomposable group).

[0153] In the resin according to the present invention, theacid-decomposable group may be contained in the group represented byformula (Ib) (for example, as R_(7b) or R_(9b)), or may be contained ina repeating unit having a group represented by formula (Ib) (forexample, as R_(27b)), or may be contained in other repeating units. Theacid-decomposable groups may be contained in two or more kinds of suchgroups or units.

[0154] Examples of the acid-decomposable group include a group which ishydrolyzed by the action of an acid to form an acid and a group whichreleases a carbon cation by the action of an acid to form an acid.Preferred examples include groups represented by formulae (XIII) and(XIV) described hereinbefore. Such acid-decomposable groups serve toimpart excellent storage stability.

[0155] The content of the structural unit having the alicyclic grouprepresented by formula (Ib) described above(preferably the repeatingunit represented by formula (IVb), (Vb) or (VIb)) in the resin accordingto the present invention is controlled while taking account of thebalance among dry etching resistance, developing property with alkaliand the like. However, the content thereof is preferably 20% by mole ormore, more preferably from 30 to 80% by mole, and still more preferablyfrom 40 to 65% by mole, based on the whole repeating unit.

[0156] The content of the repeating unit having the acid-decomposablegroup described above(preferably the repeating unit represented byformula (VIIb), (VIIIb) or (IXb)) in the resin according to the presentinvention is controlled while taking account of characteristics such asdeveloping property with alkali, adhesion to a substrate and the like.However, the content thereof is preferably from 5 to 100% by mole, morepreferably from 10 to 100% by mole, and still more preferably from 20 to100% by mole, based on the whole repeating unit. The content of theacid-decomposable group-containing repeating unit used herein means acontent of the total acid-decomposable group-containing repeating unitsin the resin, including the repeating unit having the group representedby formula (Ib) describe above which contains an acid-decomposablegroup.

[0157] Specific examples of the repeating unit represented by any one offormulae (IVb), (Vb) and (VIb) are set forth below as (a′1) to (a′10),but the present invention should not be construed as being limitedthereto.

[0158] Specific examples of the repeating unit represented by any one offormulae (VIIb), (VIIIb) and (IXb) include (c1) to (c30) set forthhereinbefore with respect to the first embodiment of the photosensitivecomposition according to the present invention, but the presentinvention should not be construed as being limited thereto.

[0159] Of the structural units having the group represented by formula(Ib) in the present invention, (a′1), (a′2) and (a′3) are particularlypreferred.

[0160] [2] Repeating structural unit having a carboxy group:

[0161] In the resin according to the present invention, a carboxy groupmay be contained in the repeating unit having the group represented byformula (Ib) described above, or may be contained in the repeating unithaving the acid-decomposable group, or may be contained in a repeatingunit other than those repeating units. Further, the carboxy groups maybe contained in two or more kinds of such positions as described above.

[0162] Of the repeating units having a carboxy group, repeating unitsrepresented by formulae (Xb), (XIb) and (XIIb) described above arepreferred.

[0163] In the formula (Xb), (XIb) or (XIIb) described above, the alkylgroup represented by any one of R_(34b), R_(35b) and R_(37b) to R_(39b)is preferably an optionally substituted alkyl group having from 1 to 4carbon atoms, for example, methyl, ethyl, propyl, n-butyl or sec-butyl.The haloalkyl group is preferably an alkyl group having from 1 to 4carbon atoms substituted with a fluorine atom, a chlorine atom or abromine atom, for example, fluoromethyl, chloromethyl, bromomethyl,fluoroethyl, chloroethyl or bromoethyl.

[0164] The alkyl group represented by any one of R_(40b) to R_(42b) andR_(45b) is preferably an optionally substituted alkyl group having from1 to 8 carbon atoms, for example, methyl, ethyl, propyl, n-butyl,sec-butyl, hexyl, 2-ethylhexyl or octyl. The cycloalkyl group ispreferably an optionally substituted cycloalkyl group having from 3 to 8carbon atoms, for example, cyclopropyl, cyclopentyl or cyclohexyl. Thealkenyl group is preferably an optionally substituted alkenyl grouphaving from 2 to 6 carbon atoms, for example, vinyl, propenyl, allyl,butenyl, pentenyl, hexenyl or cyclohexenyl.

[0165] The alkylene group represented by any one of X_(7b) to X_(9b) ispreferably an optionally substituted alkylene group having from 1 to 8carbon atoms, for example, methylene, ethylene, propylene, butylene,hexylene or octylene. The alkenylene group is preferably an optionallysubstituted alkenylene group having from 2 to 6 carbon atoms, forexample, ethenylene, propenylene or butenylene. The cycloalkylene groupis preferably an optionally substituted cycloalkylene group having from5 to 8 carbon atoms, for example, cyclopentylene or cyclohexylene.

[0166] Preferred examples of the alkylene, alkenylene and cycloalkylenegroup represented by R_(43b), R_(44b) and R_(46b) are same as thosedescribed for X_(7b) to X_(9b) above, respectively. R_(43b), R_(44b) andR_(46b) each also represents a divalent group formed by combining eachof these groups with an ether, ester, amido, urethane or ureido group.

[0167] Preferred examples of the substituent which may be possessed bythe substituents described above include a hydroxy group, a halogen atom(fluorine, chlorine, bromine, and iodine), a nitro group, a cyano group,an amido group, a sulfonamido group, an alkyl group such as the alkylgroup described with regard to R_(a) to R_(g) hereinbefore, an alkoxygroup such as methoxy, ethoxy, hydroxyethoxy, propoxy, hydroxypropoxyand butoxy, an alkoxycarbonyl group such as methoxycarbonyl andethoxycarbonyl, an acyl group such as formyl, acetyl and benzoyl, anacyloxy group such as acetoxy and butyryloxy, and a carboxy group.

[0168] The content of the repeating unit having a carboxy groupdescribed above (preferably the repeating unit represented by formula(Xb), (XIb) or (XIIb)) in the resin according to the present inventionis controlled while taking account of characteristics such as developingproperty with alkali, adhesion to a substrate, sensitivity and the like.However, the content thereof is preferably from 0 to 60% by mole, morepreferably from 0 to 40% by mole, and still more preferably from 0 to20% by mole, based on the whole repeating unit. The content of carboxygroup-containing repeating unit used herein means a content of the totalcarboxy group-containing repeating units in the resin, including therepeating unit having the group represented by formula (Ib) containing acarboxy group and the repeating unit containing an acid-decomposablegroup and a carboxy group.

[0169] Specific examples of the repeating unit represented by any one offormulae (Xb), (XIb) and (XIIb) include (d-1) to (d-18) set forthhereinbefore with respect to the first embodiment of the photosensitivecomposition according to the present invention, but the presentinvention should not be construed as being limited thereto.

[0170] [3] Resin (B) containing the repeating unit described aboveaccording to the present invention:

[0171] For the purpose of improving characteristics of the resin (B) foruse in the second embodiment of the photosensitive composition accordingto the present invention, one or more other monomers may further becopolymerized within the range of not severely impairingtransmissibility at 220 nm or less and dry etching resistance of theresin.

[0172] Copolymerizable monomers which can be used are same as thosedescribed for other polymerizable monomers with respect to the firstembodiment of the photosensitive composition according to the presentinvention.

[0173] The resin (B) according to the present invention which containsthe repeating unit having the group represented by formula (Ib)(preferably the repeating unit represented by any one of formulae (IVb)to (VIb)), the repeating unit having an acid-decomposable group(preferably the repeating unit represented by any one of formulae (VIIb)to (IXb)), the repeating unit having a carboxy group (preferably therepeating unit represented by any one of formulae (Xb) to (XIIb)), ifdesired, and a repeating unit derived from other polymerizable monomer,if desired, is synthesized by a radical, cation or anion polymerizationof unsaturated monomers corresponding to the respective structures.

[0174] More specifically, the respective monomers are mixed based on thedesired composition as described above and polymerized in an appropriatesolvent in a monomer concentration of from about 10 to 40% by weight byadding a polymerization catalyst, and if desired, by adding a chaintransfer agent, and if desired, by heating.

[0175] The resin (B) according to the present invention has a molecularweight, in terms of a weight average molecular weight (Mw: polystyrenebasis), of 2,000 or more, preferably from 3,000 to 1,000,000, morepreferably from 3,000 to 200,000, and still more preferably from 3,000to 100,000. As the molecular weight is larger, heat resistance or thelike is more improved, however, developing property or the likedeteriorates. Therefore, the molecular weight is controlled in apreferred range taking account of the balance of these characteristics.A degree of dispersion (Mw/Mn) is preferably from 1.0 to 5.0, morepreferably from 1.0 to 3.0. As the degree of dispersion is smaller, heatresistance and image performance (pattern profile, defocus latitude, orthe like) are improved.

[0176] In the present invention, the amount of the above described resinadded to the photosensitive composition is from 50 to 99.7% by weight,preferably from 70 to 99% by weight, based on the whole solid content.

[0177] Now, the compound (A) which generates an acid upon irradiationwith an actinic ray or radiation for use in the first or secondembodiment of the photosensitive composition according to the presentinvention will be described in more detail below.

[0178] The compound which generates an acid upon irradiation with anactinic ray or radiation for use in the present invention is a photoacid generator.

[0179] The compound which decomposes on irradiation of an active ray orradiation to generate an acid for use in the present invention may beappropriately selected from photoinitiators for photo-cationpolymerization, photoinitiators for photo-radical polymerization,photo-achromatizing agents, photo-discoloring agents, known compoundsused in a microresist or the like, which generate an acid by light(ultraviolet ray or far ultraviolet ray of from 200 to 400 nm,particularly preferably, g-line, h-line, i-line, KrF excimer laserbeam), an ArF excimer laser beam, an electron beam, an X ray, amolecular beam or an ion beam, and a mixture of these compounds.

[0180] Other examples of the compound generating an acid on irradiationof an actinic ray or radiation for use in the present invention includediazonium salts described in S. I. Schlesinger, Photogr. Sci. Eng., 18,387 (1974) and T. S. Bal et al., Polymer, 21, 423 (1980), ammonium saltsdescribed in U.S. Pat. Nos. 4,069,055, 4,069,056 and Re 27,992 andJP-A-3-140140, phosphonium salts described in D. C. Necker et al.,Macromolecules, 17, 2468 (1984), C. S. Wen et al., Teh, Proc. Conf. Rad.Curing ASIA, p. 478, Tokyo, Oct. (1988) and U.S. Pat. Nos. 4,069,055 and4,069,056, iodonium salts described in J. V. Crivello et al.,Macromolecules, 10(6), 1307 (1977), Chem. & Eng. News, November 28, p.31 (1988), European Patent 104143, 339049 and 410201, JP-A-2-150848 andJP-A-2-296514, sulfonium salts described in J. V. Crivello et al.,Polymer J. 17, 73 (1985), J. V. Crivello et al., J. Org. Chem., 43, 3055(1978), W. R. Watt et al., J. Polymer Sci., Polymer Chem. Ed., 22, 1789(1984), J. V. Crivello et al., Polymer Bull., 14, 279 (1985), J. V.Crivello et al., Macromolecules, 14(5), 1141 (1981), J. V. Crivello etal., J. Polymer Sci., Polymer Chem. Ed., 17, 2877 (1979), EuropeanPatents 370693, 161811, 410201, 339049, 233567, 297443 and 297442, U.S.Pat. Nos. 3,902,114, 4,933,377, 4,760,013, 4,734,444 and 2,833,827,German Patents 2,904,626, 3,604,580 and 3,604,581, JP-A-7-28237 andJP-A-8-27102, selenonium salts described in J. V. Crivello et al.,Macromolecules, 10(6), 1307 (1977), and J. V. Crivello et al., J.Polymer Sci., Polymer Chem. Ed., 17, 1047 (1979), onium salts such asarsonium salt described in C. S. Wen et al., Teh, Proc. Conf. Rad.Curing ASIA, p. 478, Tokyo, October (1988), organic halogen compoundsdescribed in U.S. Pat. No. 3,905,815, JP-B-46-4605, JP-A-48-36281,JP-A-55-32070, JP-A-60-239736, JP-A-61-169835, JP-A-61-169837,JP-A-62-58241, JP-A-62-212401, JP-A-63-70243 and JP-A-63-298339, organicmetals/organic halides described in K. Meier et al., J. Rad. Curing,13(4), 26 (1986), T. P. Gill et al., Inorg Chem., 19, 3007 (1980), D.Astruc, Acc. Chem. Res., 19(12), 377 (1896) and JP-A-2-161445,photo-acid generators having an o-nitrobenzyl type protective group,described in S. Hayase et al., J. Polymer Sci., 25, 753 (1987), E.Reichmanis et al., J. Polymer Sci., Polymer Chem. Ed., 23, 1 (1985), Q.Q. Zhu et al., J. Photochem., 36, 85, 39, 317 (1987), B. Amit et al.,Tetrahedron Lett., (24)2205 (1973), D. H. R. Barton et al., J. Chem.Soc., 3571 (1965), P. M. Collins et al., J. Chem. Soc., Perkin I, 1695(1975), M. Rudinstein et al., Tetrahedron Lett., (17), 1445 (1975), J.W. Walker et al., J. Am. Chem. Soc., 110, 7170 (1988), S. C. Busman etal., J. Imaging Technol., 11(4), 191 (1985), H. M. Houlihan et al.,Macromolecules, 21, 2001 (1988), P. M. Collins et al., J. Chem. Soc.Chem. Commun., 532 (1972), S. Hayase et al., Macromolecules, 18, 1799(1985), E. Reichmanis et al., J. Electrochem. Soc., Solid State Sci.Technol., 130(6), F. M. Houlihan et al., Macromolecules, 21, 2001(1988), European Patents 290750, 046083, 156535, 271851 and 388343, U.S.Pat. Nos. 3,901,710 and 4,181,531, JP-A-60-198538 and JP-A-53-133022,compounds which photolyze and generate a sulfonic acid, represented byiminosulfonate and the like and described in M. Tunooka et al., PolymerPreprints Japan, 35(8), G. Berner et al., J. Rad. Curing, 13(4), W. J.Mijs et al., Coating Technol., 55(697), 45 (1983) Akzo, H. Adachi etal., Polymer Preprints, Japan, 37(3), European Patents 199672, 084515,044115, 618564 and 101122, U.S. Pat. Nos. 4,371,605 and 4,431,774,JP-A-64-18143, JP-A-2-245756 and JP-A-3-140109, disulfone compoundsdescribed in JP-A-61-166544 and JP-A-2-71270, and diazoketosulfone anddiazodisulfone compounds described in JP-A-3-103854, JP-A-3-103856 andJP-A-4-210960.

[0181] Furthermore, polymer compounds having the group or compoundgenerating an acid by light introduced into the main or side chainthereof may also be used and examples thereof include compoundsdescribed in M. E. Woodhouse et al., J. Am. Chem. Soc., 104, 5586(1982), S. P. Pappas et al., J. Imaging Sci., 30(5), 218 (1986), S.Kondo et al., Makromol. Chem., Rapid Commun., 9, 625 (1988), Y. Yamadaet al., Makromol. Chem., 152, 153, 163 (1972), J. V. Crivello et al., J.Polymer Sci., Polymer Chem. Ed., 17, 3845 (1979), U.S. Pat. No.3,849,137, German Patent 3,914,407, JP-A-63-26653, JP-A-55-164824,JP-A-62-69263, JP-A-63-146038, JP-A-63-163452, JP-A-62-153853 andJP-A-63-146029.

[0182] Also, compounds which generate an acid by light described in V.N. R. Pillai, Synthesis, (1), 1 (1980), A. Abad et al., TetrahedronLett., (47) 4555 (1971), D. H. R. Barton et al., J. Chem. Soc., (C), 329(1970), U.S. Pat. No. 3,779,778 and European Patent 126712 may be used.

[0183] Among the above-described compounds which decompose onirradiation of an actinic ray or radiation and generate an acid, thosewhich can be particularly effectively used are described below.

[0184] (1) Oxazole derivative represented by formula (PAG1) shown belowor s-triazine derivative represented by formula (PAG2) shown below,substituted with trihalomethyl group:

[0185] wherein R²⁰¹ represents a substituted or unsubstituted aryl groupor an alkenyl group, R²⁰² represents a substituted or unsubstituted arylgroup, alkenyl group or alkyl group, or —C(Y)₃, and Y represents achlorine atom or a bromine atom.

[0186] Specific examples thereof include the following compounds,however, the present invention should not be construed as being limitedthereto.

[0187] (2) Iodonium salt represented by formula (PAG3) shown below orsulfonium salt represented by formula (PAG4) shown below:

[0188] wherein Ar¹ and Ar² each independently represents a substitutedor unsubstituted aryl group. Preferred examples of the substituentinclude an alkyl group, a haloalkyl group, a cycloalkyl group, an arylgroup, an alkoxy group, a nitro group, a carboxyl group, analkoxycarbonyl group, a hydroxy group, a mercapto group and a halogenatom.

[0189] R²⁰³, R₂₀₄ and R²⁰⁵ each independently represents a substitutedor unsubstituted alkyl group or an aryl group, preferably an aryl grouphaving from 6 to 14 carbon atoms, an alkyl group having from 1 to 8carbon atoms, or a substituted derivative thereof. Preferred examples ofthe substituent include, for the aryl group, an alkoxy group having from1 to 8 carbon atoms, an alkyl group having from 1 to 8 carbon atoms, anitro group, a carboxyl group, a hydroxyl group and a halogen atom, andfor the alkyl group, an alkoxy group having from 1 to 8 carbon atoms, acarboxyl group and an alkoxycarbonyl group.

[0190] Z^(—) represents a counter anion and examples thereof include aperfluoroalkane sulfonate anion such as BF₄ ^(—), AsF₆ ^(—), PF₆ ^(—),SbF₆ ^(—), SiF₆ ^(2—), ClO₄ ^(—) and CF₃SO₃ ^(—), a pentafluorobenzenesulfonate anion, a condensed polynuclear aromatic sulfonate anion suchas naphthalene-1-sulfonate anion, anthraquinone sulfonate anion, and asulfonic acid group-containing dye, however, the present inventionshould not be construed as being limited thereto.

[0191] Two of R²⁰³, R²⁰⁴ and R²⁰⁵ or Ar¹ and Ar² may be combined througha single bond or a substituent.

[0192] Specific examples thereof include the following compounds,however, the present invention should not be construed as being limitedthereto.

[0193] The onium salts represented by formulae (PAG3) and (PAG4) areknown and can be synthesized by the methods described, for example, inJ. W. Knapczyk et al., J. Am. Chem. Soc., 91, 145 (1969), A. L. Maycoket al., J. Org. Chem., 35, 2532 (1970), E. Goethas et al., Bull. Soc.Chem. Belg., 73, 546 (1964), H. M. Leicester, J. Ame. Chem. Soc., 51,3587 (1929), J. V. Crivello et al., J. Polym. Chem. Ed., 18, 2677(1980), U.S. Pat. Nos. 2,807,648 and 4,247,473, and JP-A-53-101331.

[0194] (3) Disulfone derivative represented by formula (PAG5) shownbelow or iminosulfonate derivative represented by formula (PAG6) shownbelow:

[0195] Ar³—SO₂—SO₂—Ar⁴   (PAG5)

[0196] wherein Ar³ and Ar⁴ each independently represents a substitutedor unsubstituted aryl group, R₂₀₆ represents a substituted orunsubstituted alkyl group or aryl group, and A represents a substitutedor unsubstituted alkylene group, alkenylene group or arylene group.

[0197] Specific examples thereof include the following compounds,however, the present invention should not be construed as being limitedthereto.

[0198] (4) Diazodisulfone derivative represented by formula (PAG7) shownbelow:

[0199] wherein R represents a straight-chain, branched chain or cyclicalkyl group or an aryl group which may be substituted.

[0200] Specific examples thereof include the following compounds,however, the present invention should not be construed as being limitedthereto.

[0201] The amount of the compound which decomposes on irradiation of anactinic ray or radiation and generates an acid to be used is usuallyfrom 0.001 to 40% by weight, preferably from 0.01 to 20% by weight, morepreferably from 0.1 to 5% by weight, based on the solid content of thepositive photosensitive composition. If the amount added of the compoundwhich decomposes on irradiation of an actinic ray or radiation andgenerates an acid is less than 0.001% by weight, the sensitivity isreduced, whereas if the amount added exceeds 40% by weight, the resistexhibits too much light absorption, resulting in causing disadvantageouseffects such as deterioration of profile or narrow process (particularlybake) margin.

[0202] Other components for use in the first embodiment of thephotosensitive composition according to the present invention:

[0203] The positive photosensitive composition of the present inventionmay further contain, if desired, an acid decomposable dissolutionaccelerating compound, a dye, a plasticizer, a surface active agent, aphotosensitizer, an organic basic compound, a compound which acceleratesthe solubility in a developing solution, and the like.

[0204] The compound for accelerating the dissolution in a developingsolution, which can be used in the present invention, is a low molecularcompound containing two or more phenolic OH groups or one or morecarboxyl group and having a molecular weight of 1,000 or less. In thecase where the compound contains a carboxyl group, an alicyclic oraliphatic compound is preferred from the same reason as described above.

[0205] The amount of the dissolution accelerating compound added ispreferably from 2 to 50% by weight, more preferably from 5 to 30% byweight, based on the resin according to the present invention. If theamount added exceeds 50 wt %, development residue increases adversely ora new problem disadvantageously arises such that the pattern deforms atthe development.

[0206] The above-described phenol compound having a molecular weight of1,000 or less can be easily synthesized by one skilled in the art makingreference to the methods described, for example, in JP-A-1-22938,JP-A-2-28531, U.S. Pat. No. 4,916,210 and European Patent 219294.

[0207] Specific examples of the phenol compound are described below,however, the compounds which can be used in the present invention shouldnot be construed as being limited thereto.

[0208] Resorcinol, phloroglucinol, 2,3,4-trihydroxybenzophenone,2,3,4,4′-tetrahydroxybenzophenone,2,3,4,3′,4′,5′-hexahydroxybenzophenone, acetone-pyrogallol condensedresin, phloroglucocide, 2,4,2′,4′-biphenyltetrol,4,4′-thiobis(1,3-dihydroxy)benzene, 2,2′,4,4′-tetrahydroxydiphenylether, 2,2′,4,4′-tetrahydroxydiphenyl sulfoxide,2,2′,4,4′-tetrahydroxydiphenylsulfone, tris(4-hydroxyphenyl)methane,1,1-bis(4-hydroxyphenyl)cyclohexane, 4,4-(α-methylbenzylidene)bisphenol,α,α′,α″-tris(4-hydroxyphenyl)-1,3,5-triisopropylbenzene,α,α′,α″-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene,1,2,2-tris(hydroxyphenyl)propane,1,1,2-tris(3,5-dimethyl-4-hydroxyphenyl)propane,2,2,5,5-tetrakis(4-hydroxyphenyl)-hexane,1,2-tetrakis(4-hydroxyphenyl)ethane, 1,1,3-tris(hydroxyphenyl)butane andpara [α,α,α′,α′-tetrakis(4-hydroxyphenyl)]xylene.

[0209] The organic basic compound which can be used in the presentinvention is preferably a compound having basicity stronger than thephenol, more preferably a nitrogen-containing basic compound.

[0210] The preferred chemical environment thereof includes the followingstructures (A) to (E).

[0211] wherein R²⁵⁰, R²⁵¹ and R²⁵², which may be the same or different,each represents a hydrogen atom, an alkyl group having from 1 to 6carbon atoms, an aminoalkyl group having from 1 to 6 carbon atoms, ahydroxyalkyl group having from 1 to 6 carbon atoms or a substituted orunsubstituted aryl group having from 6 to 20 carbons atoms, and R²⁵¹ andR²⁵² may combine with each other to form a ring;

[0212] wherein R²⁵³, R²⁵⁴, R²⁵⁵ and R²⁵⁶, which may be the same ordifferent, each represents an alkyl group having from 1 to 6 carbonatoms.

[0213] More preferred is a nitrogen-containing basic compound containingtwo or more nitrogen atoms of different chemical environments in onemolecule, still more preferred is a compound containing both asubstituted or unsubstituted amino group and a ring structure having anitrogen atom, or a compound having an alkylamino group. Preferredspecific examples thereof include a substituted or unsubstitutedguanidine, a substituted or unsubstituted aminopyridine, a substitutedor unsubstituted aminoalkylpyridine, a substituted or unsubstitutedaminopyrrolidine, a substituted or unsubstituted indazole, a substitutedor unsubstituted pyrazole, a substituted or unsubstituted pyrazine, asubstituted or unsubstituted pyrimidine, a substituted or unsubstitutedpurine, a substituted or unsubstituted imidazoline, a substituted orunsubstituted pyrazoline, a substituted or unsubstituted piperazine, asubstituted or unsubstituted aminomorpholine and a substituted orunsubstituted aminoalkylmorpholine. The substituent is preferably anamino group, an aminoalkyl group, an alkylamino group, an aminoarylgroup, an arylamino group, an alkyl group, an alkoxy group, an acylgroup, an acyloxy group, an aryl group, an aryloxy group, a nitro group,a hydroxyl group or a cyano group. More preferred examples of thecompound include guanidine, 1,1-dimethylguanidine,1,1,3,3-tetramethylguanidine, 2-aminopyridine, 3-aminopyridine,4-aminopyridine, 2-dimethylaminopyridine, 4-dimethylaminopyridine,2-diethylaminopyridine, 2-(aminomethyl)pyridine,2-amino-3-methylpyridine, 2-amino-4-methylpyridine,2-amino-5-methylpyridine, 2-amino-6-methylpyridine,3-aminoethylpyridine, 4-aminoethylpyridine, 3-aminopyrrolidine,piperazine, N-(2-aminoethyl)piperazine, N-(2-aminoethyl)-piperidine,4-amino-2,2,6,6-tetramethylpiperidine, 4-piperidinopiperidine,2-iminopiperidine, 1-(2-aminoethyl)-pyrrolidine, pyrazole,3-amino-5-methylpyrazole, 5-amino-3-methyl-1-p-tolylpyrazole, pyrazine,2-(aminomethyl)-5-methylpyrazine, pyrimidine, 2,4-diaminopyrimidine,4,6-dihydroxypyrimidine, 2-pyrazoline, 3-pyrazoline, N-aminomorpholine,N-(2-aminoethyl)morpholine, 1,5-diaza-bicyclo[4,3,0]non-5-ene,1,8-diazabicyclo[5,4,0]undec-7-ene and 2,4,5-triphenylimidazole.However, the present invention should not be construed as being limitedthereto.

[0214] The nitrogen-containing basic compounds are used individually orin combination of two or more thereof. The amount of thenitrogen-containing basic compound used is usually from 0.001 to 10% byweight, preferably from 0.01 to 5% by weight, based on the solid contentof the photosensitive composition. If the amount used is less than0.001% by weight, the effect owing to the addition of thenitrogen-containing basic compound may not be obtained, whereas if itexceeds 10% by weight, reduction in sensitivity or deterioration indeveloping property of the unexposed area is liable to occur.

[0215] Suitable dyes include an oil dye and a basic dye. Specificexamples thereof include Oil Yellow #101, Oil Yellow #103, Oil Pink#312, Oil Green BG, Oil Blue BOS, Oil Blue #603, Oil Black BY, Oil BlackBS, Oil Black T-505 (all are manufactured by Orient Chemical IndustriesCo., Ltd.), Crystal Violet (CI42555), Methyl Violet (CI42535), RhodamineB (CI45170B), Malachite Green (CI42000) and Methylene Blue (CI52015).

[0216] In order to improve acid generation ratio on exposure, aphotosensitizer may be added. Specific examples of suitablephotosensitizers include benzophenone,p,p′-tetramethyldiaminobenzophenone,p,p′-tetraethylethylaminobenzophenone, 2-chlorothioxanthone, anthrone,9-ethoxyanthracene, anthracene, pyrene, perylene, phenothiazine, benzil,Acridine Orange, benzoflavin, Setoflavin-T, 9,10-diphenylanthracene,9-fluorenone, acetophenone, phenanthrene, 2-nitrofluorene,5-nitroacenaphthene, benzoquinone, 2-chloro-4-nitroaniline,N-acetyl-p-nitroaniline, p-nitroaniline,N-acetyl-4-nitro-1-naphthylamine, picramide, anthraquinone,2-ethylanthraquinone, 2-tert-butylanthraquinone, 1,2-benzanthraquinone,3-methyl-1,3-diaza-1,9-benzanthrone, dibenzalacetone,1,2-naphthoquinone, 3,3′-carbonyl-bis(5,7-dimethoxycarbonylcoumarin) andcoronene. However, the present invention should not be construed asbeing limited thereto.

[0217] The photosensitizer may also be used as a light absorbent of farultraviolet light from a light source. In this case, the absorbentreduces reflected light from a substrate and decreases the influence ofmultiple reflection in the resist layer, thereby exerting the effect ofimproving the standing wave.

[0218] The photosensitive composition of the present invention isdissolved in a solvent which can dissolve the above-described respectivecomponents, and then coated on a support. The solvent used is preferablyethylene dichloride, cyclohexanone, cyclopentanone, 2-heptanone,γ-butyrolactone, methyl ethyl ketone, ethylene glycol monomethyl ether,ethylene glycol monoethyl ether, 2-methoxyethyl acetate, ethylene glycolmonoethyl ether acetate, propylene glycol monomethyl ether, propyleneglycol monomethyl ether acetate, toluene, ethyl acetate, methyl lactate,ethyl lactate, methyl methoxypropionate, ethyl ethoxypropionate, methylpyruvate, ethyl pyruvate, propyl pyruvate, N,N-dimethylformamide,dimethyl sulfoxide, N-methylpyrrolidone or tetrahydrofuran. The solventsare used individually or in combination of two or more thereof.

[0219] In the present invention, a surface active agent other than thefluorine-base and/or silicon-base surface active agent (F) describedabove may be added. Specific examples thereof include a nonionic surfaceactive agent, for example, polyoxyethylene alkyl ethers such aspolyoxyethylene lauryl ether, polyoxyethylene stearyl ether,polyoxyethylene cetyl ether and polyoxyethylene oleyl ether,polyoxyethylene alkylaryl ethers such as polyoxyethylene octylphenolether and polyoxyethylene nonylphenol ether,polyoxyethylene/polyoxypropylene block copolymers, sorbitan fatty acidesters such as sorbitan monolaurate, sorbitan monopalmitate, sorbitanmonostearate, sorbitan monooleate, sorbitan trioleate and sorbitantristearate, and polyoxyethylene sorbitan fatty acid esters such aspolyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitanmonopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylenesorbitan trioleate and polyoxyethylene sorbitan tristearate. The amountof the surface active agent used is usually 2% by weight or less,preferably 1% by weight or less, based on the solid content of thephotosensitive composition of the present invention.

[0220] The surface active agents may be used individually or incombination of two or more thereof.

[0221] Other components for use in the second embodiment of thephotosensitive composition according to the present invention:

[0222] The positive photosensitive composition of the present inventionmay further contain, if desired, an acid decomposable dissolutioninhibiting compound, and a dye, a plasticizer, a surface active agent, aphotosensitizer, an organic basic compound, a compound which acceleratesthe dissolution in a developing solution, and the like as describedregarding to the first embodiment of the photosensitive compositionabove.

[0223] The acid decomposable dissolution inhibiting compound for use inthe present invention includes a low molecular weight compoundcontaining at least one acid-decomposable group represented by formula(XIII) or (XIV) and having a molecular weight of 3,000 or less. In orderto prevent reduction in the transmittance particularly at 220 nm orless, an alicyclic or aliphatic compound such as a cholic acidderivative described in Proceeding of SPIE, 2724, 355 (1996) ispreferred. In the present invention, when the acid decomposabledissolution inhibiting compound is used, the amount thereof added isfrom 3 to 50% by weight, preferably from 5 to 40% by weight, morepreferably from 10 to 35% by weight, based on the whole weight of thephotosensitive composition (excluding the solvent).

[0224] The second embodiment of the photosensitive composition accordingto the present invention is also dissolved in a solvent which candissolve the above-described respective components, and then coated on asupport. Specific examples of the solvent used are same as thosedescribed for the first embodiment of the photosensitive compositionabove.

[0225] To the solvent, a surface active agent may be added. Specificexamples thereof include a nonionic surface active agent, for example,polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether,polyoxyethylene stearyl ether, polyoxyethylene cetyl ether andpolyoxyethylene oleyl ether, polyoxyethylene alkylaryl ethers such aspolyoxyethylene octylphenol ether and polyoxyethylene nonylphenol ether,polyoxyethylene/polyoxypropylene block copolymers, sorbitan fatty acidesters such as sorbitan monolaurate, sorbitan monopalmitate, sorbitanmonostearate, sorbitan monooleate, sorbitan trioleate and sorbitantristearate, and polyoxyethylene sorbitan fatty acid esters such aspolyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitanmonopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylenesorbitan trioleate and polyoxyethylene sorbitan tristearate; afluorine-base surface active agent such as F-top EF301, EF303 and EF352(manufactured by Shin Akita Chemical Co., Ltd.), Megafac F171 and F173(manufactured by Dainippon Ink and Chemicals, Inc.), Fluorad FC430 andFC431 (both manufactured by Sumitomo 3M Ltd.), Asahiguard AG710, SurflonS-382, SC101, SC102, SC103, SC104, SC105 and SC-106 (manufactured byAsahi Glass Co., Ltd.), organosiloxane polymer KP-341 (manufactured byShin-Etsu Chemical Co., Ltd.), and acrylic acid-base or methacrylicacid-base (co)polymer Polyflow No. 75 and No. 95 (manufactured byKyoeisha Yushi Kagaku Kogyo Co., Ltd.). The amount of the surface activeagent added is ordinarily 2 parts by weight or less, preferably 1 partby weight or less, per 100 parts by weight of the solid content in thephotosensitive composition according to the present invention.

[0226] The surface active agents may be used individually or incombination of two or more thereof.

[0227] The above-described first or second embodiment of thephotosensitive composition is coated on a substrate (e.g.silicon/silicon dioxide coating) for use in the production of aprecision integrated circuit element by an appropriate coating meanssuch as spinner or coater, exposed through a predetermined mask, bakedand developed to thereby obtain a good resist pattern.

[0228] The exposure light is preferably far ultraviolet light having awavelength of 250 nm or less, more preferably 220 nm or less. Specificexamples thereof include KrF excimer laser (248 nm), ArF excimer laser(193 m), F₂ excimer laser (157 nm), X ray and an electron beam.

[0229] A developing solution which can be used for the photosensitivecomposition according to the present invention is an alkaline aqueoussolution of an inorganic alkali such as sodium hydroxide, potassiumhydroxide, sodium carbonate, sodium silicate, sodium metasilicate andaqueous ammonia, a primary amine such as ethylamine and n-propylamine, asecondary amine such as diethylamine and di-n-butylamine, a tertiaryamine such as triethylamine and methyldiethylamine, an alcohol aminesuch as dimethylethanolamine and triethanolamine, a quaternary ammoniumsalt such as tetramethylammonium hydroxide and tetraethylammoniumhydroxide, and a cyclic amine such as pyrrole and piperidine.

[0230] To the alkaline aqueous solution, an appropriate amount of analcohol or surface active agent may be added.

EXAMPLES

[0231] The present invention will be described in greater detail withreference to the following examples, however, the present inventionshould not be construed as being limited thereto.

Synthesis Example 1

[0232] Synthesis of Raw Material Monomer for Repeating Unit (a1)

[0233] In 500 ml of isopropyl alcohol, 25 g of γ-crotonolactone wasdissolved and the resulting solution was irradiated with a low-pressuremercury lamp (6 W, manufactured by Usio Inc.) in a quartz photoreactionapparatus for 80 hours. The reaction solution was filtered and isopropylalcohol was distilled off to obtain a crude product. The crude productwas purified by distillation under a reduced pressure to obtain 31 g ofan alcohol compound.

[0234] In 100 ml of tetrahydrofuran, 9.3 g (64.6 mmol) of the alcoholcompound thus-obtained was dissolved, and to the solution were added12.8 g (129.2 mmol) of triethylamine and 0.7 g ofN,N-dimethylaminopyridine. To the solution was dropwise added 10.1 g(96.9 mmol) of methacrylic chloride under cooling with ice over a periodof 30 minutes and the mixture was stirred for 2 hours under cooling withice and then for 3 hours at room temperature. Water was added to thereaction solution and the mixture was stirred for some time, then ethylacetate was added thereto, followed by separation. The organic layer waswashed with water and then with brine, dried and concentrated to obtaina crude product. The crude product was purified by column chromatographyto obtain 2.7 g of the desired compound.

Synthesis Example 2

[0235] Synthesis of Raw Material Monomer for Repeating Unit (a2)

[0236] Raw material monomer for repeating unit (a2) is obtained in thesame manner as in Synthesis Example 1 above expect for changingmethacrylic chloride used in Synthesis Example 1 to acrylic chloride.

Synthesis Example 3

[0237] Synthesis of Raw Material Monomer for Repeating Unit (a3)

[0238] Raw material monomer for repeating unit (a3) is obtained in thesame manner as in Synthesis Example 1 above expect for changingisopropyl alcohol used in Synthesis Example 1 to cyclohexanol.

[0239] In the same manner as described above, an α,β-unsaturatedcarbonyl compound and a secondary alcohol were subjected tophotoreaction to prepare a tertiary alcohol, and then the latter wasreacted with the corresponding acid chloride, acid anhydride orisocyanate to obtain raw material monomers for repeating units (a4) to(a36), respectively.

Synthesis Example 4

[0240] Synthesis of Raw Material Monomer for Repeating Unit (a39)

[0241] In 80 ml of methyl isobutyl ketone, 19.8 g ofα-bromo-γ-butyrolactone and 25 g of 2-hydroxyisobutyrate were dissolvedand to the resulting solution was added 36 g of triethylamine. Themixture was reacted at room temperature for 10 hours and the solid thusdeposited was filtered. The filtrate was washed with a 5% aqueous sodiumhydrogen carbonate solution, distilled water and a saturated sodiumchloride solution, dried and concentrated to obtain 11.7 g of a crudeproduct.

[0242] The crude product was dissolved in 100 ml of tetrahydrofuran, andto the solution were added 12.7 g of triethylamine and 0.1 g ofN,N-dimethylaminopyridine. To the solution was dropwise added 9.8 g ofmethacrylic chloride over a period of 30 minutes and the mixture wasreacted for 20 hours at room temperature. To the reaction solution wasadded 100 ml of distilled water, and the mixture was stirred for 30minutes and then extracted with ethyl acetate. The organic layer waswashed with water, dried and concentrated to obtain a crude product. Thecrude product was purified by column chromatography to obtain 7.2 g ofthe desired compound.

Synthesis Example 5

[0243] Synthesis of Raw Material Monomer for Repeating Unit (a41)

[0244] In 80 ml of methanol, 9 g of sodium borohydride was dissolved andto the resulting solution was added dropwise 15 g ofα-acetyl-γ-butyrolactone over a period of 30 minutes. After reacting atroom temperature for 5 hours, 4.5 g of sodium borohydride was added tothe mixture, followed by reacting for 5 hours. To the reaction solutionwas added 100 ml of water and hydrochloric acid was added thereto untilthe solution indicated week acidic property. The solution wasconcentrated and ethyl acetate was added thereto. After removing theinsoluble substance by filtration, the filtrate was concentrated toobtain a crude product. The crude product was purified by columnchromatography to obtain 10.5 g of an alcohol compound.

[0245] In 50 ml of tetrahydrofuran, 3 g of the alcohol compoundthus-obtained was dissolved, and to the solution were added 2.3 g oftriethylamine and 0.05 g of N,N-dimethylaminopyridine. To the solutionwas dropwise added 2.4 g of methacrylic chloride over a period of 30minutes and the mixture was reacted for 2 hours at room temperature. Tothe reaction solution was added 100 ml of distilled water, and themixture was stirred for 30 minutes and then extracted with ethylacetate. The organic layer was washed with water, dried and concentratedto obtain a crude product. The crude product was purified by columnchromatography to obtain 3.9 g of the desired compound.

Synthesis Example 6

[0246] Synthesis of Methyl-2-adamantyl Methacrylate (b1)

[0247] In 300 ml of tetrahydrofuran, 30 g of 2-methyl-2-adamantanol, 36g of triethylamine and 4 g of N,N-dimethylaminopyridine were dissolved,and to the solution was dropwise added 29 g of methacrylic chlorideunder cooling with ice over a period of 30 minutes. The temperature ofthe solution was raised to room temperature and reacted as it wasovernight. To the reaction solution was added 500 ml of distilled waterunder cooling with ice and then extracted with ethyl acetate. Theorganic layer was dried and concentrated to obtain a crude product. Thecrude product was purified by column chromatography to obtain 17 g ofthe desired compound.

Synthesis Example 7

[0248] Synthesis of Cedrol Acrylate (b5)

[0249] In 200 ml of tetrahydrofuran, 25 g of (+)-Cedrol (manufactured byLancaster) was dissolved, and to the solution were added 22.8 g oftriethylamine and 1 g of N,N-dimethylaminopyridine. To the solution wasdropwise added 15.2 g of acrylic chloride under cooling with ice over aperiod of 30 minutes and the mixture was stirred at room temperature for2 days. To the reaction solution was added 100 ml of distilled waterunder cooling with ice, and the mixture was stirred for 30 minutes and300 ml of ethyl acetate was added thereto. The water layer was removedby separation and the organic layer was washed with water, dried andconcentrated to obtain a crude product. The crude product was purifiedby column chromatography to obtain 18.2 g of the desired compound whichis a raw material monomer for repeating unit (b5).

Synthesis Example 8

[0250] Synthesis of Polymer (P1) According to the Present Invention

[0251] In 30 ml of N,N-dimethylacetamide, 10 g of Raw Material Monomerfor Repeating Unit (a3), 0.05 g of2′,2′-azobis(2,4-dimethylvaleronitrile) (V-65 manufactured by Wako PureChemical Industries, Ltd.) as a polymerization initiator and 0.15 g ofmercaptoacetic acid were dissolved, and the resulting solution washeated at 60° C. under a nitrogen gas stream and dropwise added to 10 mlof N,N-dimethylacetamide over a period of 4 hours. Two hours after thecompletion of the addition, 0.50 g of V-65 was added thereto, followedby reacting under heating for 2 hours. The reaction solution was allowedto cool and poured into one liter of ion exchanged water, and the soliddeposited was collected by filtration. The solid was dissolved in 100 mlof tetrahydrofuran, the solution was poured into one liter of hexane,and the solid deposited was collected by filtration to obtain Polymer(P1) containing Repeating Unit (a3). A weight average molecular weightof the polymer was 7,300 and a degree of dispersion thereof was 2.8.

Synthesis Example 9

[0252] Synthesis of Polymer (P2) According to the Present Invention

[0253] In 8.2 g of N,N-dimethylacetamide, 1.2 g of Raw Material Monomerfor Repeating Unit (al), 1.36 g of Raw Material Monomer for RepeatingUnit (b1), 0.16 g of 2′,2′-azobis(2,4-dimethylvaleronitrile) and 0.043 gof mercaptoacetic acid were dissolved, and 1.4 g of tetrahydrofuran wasadded thereto. The resulting solution was heated at 60° C. under anitrogen gas stream and 2 g of N,N-dimethylacetamide was dropwise addedthereto over a period of 4 hours. Two hours after the completion of theaddition, 0.16 g of 2′,2′-azobis(2,4-dimethylvaleronitrile) was addedthereto, followed by reacting under heating for 2 hours. The reactionsolution was allowed to cool and poured into one liter of ion exchangedwater, and the solid deposited was collected by filtration. The solidwas dissolved in 100 ml of tetrahydrofuran, the solution was poured intoone liter of hexane, and the solid deposited was collected by filtrationto obtain Polymer (P2). A weight average molecular weight of the polymerwas 6,500 and a degree of dispersion thereof was 2.0.

[0254] In the same manner as described in Synthesis Examples 8 and 9,Polymers (P3) to (P25) were synthesized using raw material monomerscorresponding to the repeating units shown in Table 1 below,respectively. In addition to the repeating units, the molar ratio of theraw material monomers used and the weight average molecular weight anddegree of dispersion of the resin obtained are also shown in Table 1.TABLE 1 Repeating Unit and Molecular Weight of Resins of the PresentInvention Weight Average Resin of Molecular Weight the Present RepeatingUnit Used (degree of Invention (molar ratio) dispersion) (P1)  (a3) 7300 (2.3) (100) (P2)  (a1)/(b1)  6500 (2.0) (50/50) (P3)  (a2)/(b2)10500 (3.0) (50/50) (P4)  (a3)/(b5)  8200 (2.2) (60/40) (P5) (a20)/(b10)  6300 (3.0) (40/60) (P6)  (a31)/(b11)  7600 (1.6) (50/50)(P7)  (a21)/(tert-butyl methacrylate) 12300 (2.5) (70/30) (P8)  (a5)/(b43) 24000 (2.8) (40/60) (P9)  (a15)/(tert-butyl methacrylate/ 5700 (1.5) acrylic acid) (80/10/10) (P10) (a16)/(b34)  5900 (1.8)(60/40) (P11) (a39)/(b1)   7500 (1.8) (50/50) (P12) (a41)/(b1)   5500(1.9) (50/50) (P13) (a43)/(b2)  11500 (2.1) (50/50) (P14)(a39)/(b1)/methacrylic acid  8900 (2.0) (40/50/10) (P15) (a51)/(b1) 14600 (2.0) (50/50) (P16) (a53)/(b51) 12800 (2.1) (60/40) (P17)(a52)/(b2)/methacrylic acid 21300 (2.3) (50/40/10) (P18) (a54)/(b53)18600 (1.9) (55/45) (P19) (a39)/(b51) 11900 (2.2) (60/40) (P20)(a39)/(b51)/methacrylic acid 25800 (2.5) (45/45/10) (P21) (a55)/(b1)  8900 (1.7) (50/50) (P22) (a57)/(b1)/methacrylic acid  7000 (1.8)(44/44/12) (P23) (a59)/(b51) 13300 (2.0) (40/60) (P24) (a55)/(b51)  6400(1.7) (50/50) (P25) (a55)/(b2)  31100 (2.5) (55/45)

Example 1

[0255] Measurement of Optical Density

[0256] In 4.5 g of propylene glycol monomethyl ether acetate, 1.0 g ofthe resin obtained in the synthesis example described above according tothe present invention and 0.03 g of triphenylsulfonium triflate weredissolved, and the resulting solution was filtered through a Teflonfilter of 0.2 μm. The solution was uniformly coated on a quartz glasssubstrate by a spin coater and died by heating on a hot plate at 100° C.for 90 seconds to form a resist film having a thickness of 1 μm. Opticalabsorption of the resulting film was measured by an ultravioletspectrophotometer. The optical density at 193 nm is shown in Table 2below. TABLE 2 Results of Optical Density Measurement of Resins of thePresent Invention Resin of the Optical Density Present Invention at 193nm (/μm) (P1)  0.38 (P2)  0.40 (P3)  0.37 (P4)  0.43 (P5)  0.34 (P6) 0.37 (P7)  0.45 (P8)  0.40 (P9)  0.33 (P10) 0.35 Poly 1.5 (p-hydroxystyrene) or more (Comparison)

[0257] It can be seen from the results shown in Table 2 that the opticaldensity value measured of each of the resins according to the presentinvention is smaller than the value of poly(p-hydroxystyrene) forcomparison and the resins have sufficiently high transmittance to thelight of 193 nm.

Example 2

[0258] Measurement of Dry Etching Resistance

[0259] In 4.5 g of propylene glycol monomethyl ether acetate, 1.0 g ofthe resin obtained in the synthesis example described above according tothe present invention was dissolved, and the resulting solution wasfiltered through a Teflon filter of 0.2 μm. The solution was uniformlycoated on a silicon substrate by a spin coater and died by heating on ahot plate at 100° C., for 90 seconds to form a resist film having athickness of 0.7 μm. The film obtained was measured on a etching rate ofCF₄/O₂ (8/2) gas using a reactive ion etching apparatus (CSE-1110manufactured by ULVAC) under the etching conditions of power of 500 W,pressure of 4.6 Pa and gas flow rate of 10 sccm. The results obtainedare shown in Table 3 below. TABLE 3 Results of Dry Etching ResistanceMeasurement of Resins of the Present Invention Resin of the PresentInvention Etching Rate (Å/min) (P1)  700 (P2)  750 (P3)  810 (P4)  700(P5)  680 (P6)  740 (P7)  780 (P8)  700 (P9)  720 (P10) 710 Poly (methylmethacrylate) 1250  (Comparison) Polymer (1) 960 (Comparison) Polymer(2) 830 (Comparison)

[0260] Polymer (1):

[0261] Tricyclodecanyl methacrylate/tetrahydropyranylmethacrylate/methacrylic acid (50/30/20 in molar ratio) copolymer(weight average molecular weight: 32,500; degree of dispersion: 2.7)

[0262] Polymer (2):

[0263] 2-Methyladamantyl methacrylate/methacrylic acid (±)-mevaloniclactone ester (synthesized by the method described in JP-A-9-90637)

[0264] It can be seen from the results shown in Table 3 that the etchingrate of each of the resins according to the present invention is smallerthan that of poly(methyl methacrylate), Polymer (1) or Polymer (2) forcomparison and have a sufficiently high dry etching resistance.

Example 3

[0265] Evaluation of Image

[0266] In 4.5 g of propylene glycol monomethyl ether acetate, 1.0 g ofthe resin obtained in the synthesis example described above according tothe present invention, 0.03 g of triphenylsulfonium triflate and 0.004 gof 1,5-diazabicyclo[4,3,0]non-5-ene were dissolved, and the resultingsolution was filtered through a Teflon filter of 0.2 μm. The solutionwas uniformly coated on a silicon substrate which had been subjected tohexamethyldisilazane treatment by a spin coater and died by heating on ahot plate at 100° C. for 90 seconds to form a resist film having athickness of 0.4 μm. The resist film was subjected to pattern exposureusing KrF excimer laser stepper (NA=0.42; 248 nm) and heated on a hotplate at 110° C. for 60 seconds immediately after the exposure. Then theresist film was developed by immersing it in a 2.38% aqueoustetramethylammonium hydroxide solution at 23° C. for 60 seconds, rinsedwith pure water for 30 seconds and dried.

[0267] A pattern form, sensitivity and resolution were evaluated witheach resist pattern obtained. Specifically, the pattern form wasdetermined by observation of the pattern obtained through a scanningelectron microscope and a pattern in a rectangular form was evaluatedgood.

[0268] The sensitivity was evaluated using an exposure amount necessaryfor reproducing a mask pattern of 0.35 μm.

[0269] The resolution was evaluated using limiting resolution in anexposure amount necessary for reproducing a mask pattern of 0.35 μm.

[0270] As a result, with the sensitivity and resolution as shown inTable 4 below, good positive pattern wherein only the exposed portion ofthe resist film was dissolved out was obtained. TABLE 4 Resin of theSensitivity Resolution Pattern Present Invention (mJ/cm²) (μm) Form(P1)  22 0.26 good (P2)  21 0.27 good (P3)  24 0.25 good (P4)  26 0.26good (P5)  18 0.25 good (P6)  21 0.27 good (P7)  23 0.25 good (P8)  220.26 good (P9)  20 0.27 good (P10) 27 0.25 good Polymer (2) 30 0.28 good

[0271] It can be seen from the results shown in Table 4 that the resistusing the resin according to the present invention exhibits highsensitivity and good resolution. Further, a good pattern form wasobtained using the resin according to the present invention.

Example 4

[0272] Evaluation of Image

[0273] On each of the resist films having a thickness of 0.4 μm obtainedin Example 3, a mask prepared by drawing a pattern with chromium on aquartz plate was closely contacted and an ArF excimer laser beam (193nm) was irradiated thereto. The resist film was heated on a hot plate at110° C. for 60 seconds immediately after the exposure. Then the resistfilm was developed by immersing it in a 2.38% aqueoustetramethylammonium hyrdoxide solution at 23° C. for 60 seconds, rinsedwith pure water for 30 seconds and dried. As a result, with thesensitivity and resolution as shown in Table 5 below, good positivepattern wherein only the exposed portion was dissolved out was obtained.

[0274] Further, the photosensitive resin composition prepared in Example3 was uniformly coated on a silicon substrate which had been subjectedto hexamethyldisilazane treatment by a spin coater and died by heatingon a hot plate at 120° C. for 90 seconds to form a resist film having athickness of 0.50 μm. The resist film was exposed to an ArF excimerlaser beam through a mask and heated on a hot plate at 110° C. for 90seconds immediately after the exposure. Then the resist film wasdeveloped with a 2.38% by weight aqueous tetramethylammonium hydroxidesolution at 23° C. for 60 seconds, rinsed with pure water for 30 secondsand dried. The sample having a contact hole pattern formed thereon wasexamined by KLA 2112 (manufactured by KLA Tencol Co., Ltd.) to measure anumber of development defects (Number of Development Defects I)(Threshould: 12; Pixcel Size: 0.39). The results obtained are also shownin Table 5 below. TABLE 5 Resin of the Number of Present SensitivityResolution Pattern Development Invention (mJ/cm²) (μm) Form Defects I(P1)  20 0.23 good  8 (P2)  16 0.23 good 10 (P3)  20 0.23 good  5 (P4) 21 0.23 good  9 (P5)  17 0.23 good 14 (P6)  22 0.23 good 12 (P7)  200.23 good  5 (P8)  21 0.23 good 15 (P9)  20 0.23 good 11 (P10) 21 0.23good 10 (P11) 13 0.21 good  9 (P12) 28 0.23 good 14 (P13) 20 0.23 good14 (P14) 14 0.21 good 12 (P15) 12 0.21 good  2 (P16) 15 0.22 good  4(P17) 14 0.21 good  3 (P18) 15 0.22 good  4 (P19) 14 0.21 good  3 (P20)13 0.21 good  4 (P21) 13 0.21 good  4 (P22) 14 0.21 good  2 (P23) 120.21 good  3 (P24) 14 0.21 good  4 (p25) 13 0.21 good  4 Polymer (2) 360.25 good 29 (Comparison) Polymer (3) 48 0.25 good 40 (Comparison)

[0275] Polymer (3):

[0276] 2-Methyl-2-adamantyl methacrylate/α-methacryloxy-γ-butyrolactonecopolymer (synthesized by the method described in EP-A-856,773)

[0277] With all of the polymers shown in Table 5, peeling off of thefilm did not occur at the development of fine patterns.

[0278] It can be seen from the results shown in Table 5 that the resistusing the resin according to the present invention exhibits goodsensitivity and resolution and forms a good positive pattern having asmall number of development defects in case of using an ArF excimerlaser beam.

Example 5

[0279] Evaluation of Image

[0280] To each of the photosensitive resin compositions prepared inExample 3 was added 0.005 g of each of the surface active agents shownin Table 6 below, and using the resulting composition a resist film wasprepared. The resist film was subjected to the same procedure such asthe heating, development, rinsing and drying as described for theexamination of Number of Development Defects I in Example 4 except foreliminating the exposure (Number of Development Defects II). The resultsobtained are shown in Table 6 below. TABLE 6 Resin of the PresentSurface Active Number of Development Invention Agent Defects II (P1)  W118 (P2)  W2 19 (P3)  W3 12 (P4)  W1 20 (P5)  W1 33 (P6)  W2 28 (P7)  W315 (P8)  W1 29 (P9)  W1 28 (P10) W2 28 (P11) W1 14 (P12) W2 20 (P13) W327 (P14) W1 25 (P15) W1 11 (P16) W2 16 (P17) W3 13 (P18) W2 11 (P19) W310 (P20) W1 10 (P21) W1 11 (P22) W2 12 (P23) W3 12 (P24) W2 13 (p25) W311

[0281] W-1: Megafac F176 (manufactured by Dainippon Ink and Chemicals,Inc.) (fluorine-base)

[0282] W-2: Megafac R₀₈ (manufactured by Dainippon Ink and Chemicals,Inc.) (fluorine-base and silicon-base)

[0283] W-3: Polysiloxane polymer KP-341 (manufactured by Shin-EtsuChemical Co., Ltd.) (silicon-base)

[0284] It can be seen from the results shown in Table 6 that the resincomposition containing a fluorine-base and/or silicon-base surfaceactive agent according to the present invention has a small number ofdevelopment defects.

[0285] As is apparent from the description above, the positivephotosensitive composition containing the resin according to the presentinvention has high transmittance to far ultraviolet light particularlyhaving a wavelength of 220 nm or less and exhibits good dry etchingresistance and adhesion and a reduced number of development defect.Further, the positive photosensitive composition exhibits highsensitivity, good resolution and good pattern profile when farultraviolet light having a wavelength of 250 nm or less, particularly220 nm or less (especially an ArF excimer laser beam) is employed as anexposure light source, and thus it can be effectively employed for theformation of fine pattern necessary for the production of semiconductorelements.

Synthesis Example 10

[0286] Synthesis of Raw Material Monomer for Repeating Unit (a′1)

[0287] In 200 ml of tetrahydrofuran, 25 g of (+)-Cedrol (manufactured byLancaster) was dissolved, and to the solution were added 22.8 g oftriethylamine and 1 g of N,N-dimethylaminopyridine. To the solution wasdropwise added 15.2 g of acrylic chloride under cooling with ice over aperiod of 30 minutes and the mixture was stirred at room temperature for2 days. To the reaction solution was added 100 ml of distilled waterunder cooling with ice, and the mixture was stirred for 30 minutes and300 ml of ethyl acetate was added thereto. The water layer was removedby separation and the organic layer was washed with water, dried andconcentrated to obtain a crude product. The crude product was purifiedby column chromatography to obtain 18.2 g of the desired compound whichis a raw material monomer for repeating unit (a′1).

Synthesis Example 11

[0288] Synthesis of Raw Material Monomer for Repeating Unit (a′2)

[0289] Raw material monomer for repeating unit (a′2) is obtained in thesame manner as in Synthesis Example 10 above expect for employingmethacrylic chloride in place of acrylic chloride used in SynthesisExample 10.

Synthesis Example 12

[0290] Synthesis of Raw Material Monomer for Repeating Unit (a′3)

[0291] Raw material monomer for repeating unit (a′3) is obtained in thesame manner as in Synthesis Example 10 above expect for employing thecompound shown below in place of (+)-Cedrol used in Synthesis Example10.

[0292] Other monomers can be obtained in the same manner as describedabove by reacting the corresponding alcohol with the corresponding acidchloride, acid anhydride or isocyanate, respectively.

Synthesis Example 13

[0293] Synthesis of Polymer (P1) composed of Unit (a′1)/Unit(cl)/acrylonitrile According to the Present Invention

[0294] In 70 ml of 1-methoxy-2-propanol, 13.1 g of Raw Material Monomerfor Repeating Unit (a′1), 3.6 g of Unit (c1) and 1.59 g of acrylonitrilewere dissolved, and to the solution was added 100 mg of2′,2′-azobis(2,4-dimethylvaleronitrile) (V-65 manufactured by Wako PureChemical Industries, Ltd.) as a polymerization initiator with stirringat 70° C. under a nitrogen gas stream. Two hours and 4 hours after theinitiation of the reaction, each 100 mg of V-65 was added thereto,followed by reacting for 3 hours and then at 90° C. for one hour. Thereaction solution was allowed to cool and poured into one liter of ionexchanged water, and the solid deposited was collected by filtration anddried to obtain Polymer (P1) (45/30/25 in molar ratio) according to thepresent invention. A weight average molecular weight of the polymermeasured by GPC and indicated in terms of polystyrene was 15,000 and adegree of dispersion thereof was 2.6.

[0295] In the same manner as described in Synthesis Example 13, theresins according to the present invention were synthesized using rawmaterial monomers corresponding to the repeating units shown in Table 7below, respectively. In addition to the repeating units, the molar ratioof the raw material monomers used and the weight average molecularweight and degree of dispersion of the resin purified are also shown inTable 7. TABLE 7 Synthesis of Resins of the Present Invention WeightAverage Resin of the Repeating Unit Used Molecular Weight PresentInvention (molar ratio) (degree of dispersion) (P2)  (a′1)/(c6)/(d2) 12600 (2.7) (50/30/20) (P3)  (a′2)/(c1)   7100 (1.9) (50/50) (P4) (a′2)/(c14) 13500 (1.5) (50/50) (P5)  (a′3)/(c12)/(d8)  18000 (3.1)(55/30/15) (P6)  (a′4)/(c15)/(d14)  9400 (2.9) (55/30/15) (P7) (a′5)/(c19)/(d18) 21000 (3.0) (50/30/20) (P8)  (a′6)/(c29)/(d2)  28000(2.7) (55/30/15) (P9)  (a′7)/(c14) 32700 (2.8) (50/50) (P10) (a′8)/(c18) 6400 (2.6) (40/60)

[0296] Synthesis of Polymer (2) for Comparison

[0297] 2-Methyladamantyl methacrylate/tert-butyl methacrylate (50/50 inmolar ratio) copolymer was synthesized according to the method describedin JP-A-9-73173. The weight average molecular weight of the copolymerwas 6,500 and the degree of dispersion thereof was 2.0.

[0298] Synthesis of Polymer (3) for Comparison

[0299] 2-Methyladamantyl methacrylate/methacrylic acid (±)-mevaloniclactone ester (47/53 in molar ratio) copolymer was synthesized accordingto the method described in JP-A-9-90637. The weight average molecularweight of the copolymer was 14,500 and the degree of dispersion thereofwas 1.80.

Example 6

[0300] Measurement of Optical Density

[0301] A resist film was prepared in the same manner as in Example 1.Optical absorption of the resulting film was measured by an ultravioletspectrophotometer. The optical density at 193 nm is shown in Table 8below. TABLE 8 Results of Optical Density Measurement of Resins of thePresent Invention Resin of the Present Invention Optical Density at 193mn (/μm) (P1)  0.39 (P2)  0.42 (P3)  0.38 (P4)  0.42 (P5)  0.37 (P6) 0.39 (P7)  0.40 (P8)  0.42 (P9)  0.35 (P10) 0.37 Polymer (2) 0.42(Comparison) Polymer (3) 0.43 (Comparison) Poly (p-hydroxystyrene) 1.5 (Comparison) or more

[0302] It can be seen from the results shown in Table 8 that the opticaldensity value measured of each of the resins according to the presentinvention is smaller than the value of poly(p-hydroxystyrene) forcomparison and the resins have sufficiently high transmittance to thelight of 193 nm.

Example 7

[0303] Measurement of Dry Etching Resistance

[0304] A resist film was prepared in the same manner as in Example 2.The film obtained was measured on a etching rate of CF₄/O₂ (8/2) gasusing a reactive ion etching apparatus (CSE-1110 manufactured by ULVAC)under the etching conditions of power of 500 W, pressure of 4.6 Pa andgas flow rate of 10 sccm. The results obtained are shown in Table 9below. TABLE 9 Results of Dry Etching Resistance Measurement of Resinsof the Present Invention Resin of the Present Invention Etching Rate(Å/min) (P1)  800 (P2)  770 (P3)  800 (P4)  720 (P5)  690 (P6)  730(P7)  710 (P8)  730 (P9)  750 (P10) 720 Poly (methyl methacrylate) 1250 (Copolymer) Polymer (1) 940 (Comparison) Polymer (2) 870 (Comparison)Polymer (3) 920 (Comparison)

[0305] Polymer (1):

[0306] Tricyclodecanyl methacrylate/tetrahydropyranylmethacrylate/methacrylic acid (50/30/20 in molar ratio) copolymer(weight average molecular weight: 32,500; degree of dispersion: 2.7)

[0307] It can be seen from the results shown in Table 9 that the etchingrate of each of the resins according to the present invention is smallerthan that of poly(methyl methacrylate), Polymer (1), Polymer (2) orPolymer (3) for comparison and have a sufficiently high dry etchingresistance.

Example 8

[0308] Evaluation of Image

[0309] In 4.5 g of propylene glycol monomethyl ether acetate, 1.0 g ofthe resin obtained in the synthesis example described above according tothe present invention and 0.03 g of triphenylsulfonium triflate weredissolved, and the resulting solution was filtered through a Teflonfilter of 0.2 μm. The solution was uniformly coated on a siliconsubstrate which had been subjected to hexamethyldisilazane treatment bya spin coater and died by heating on a hot plate at 100° C. for 90seconds to form a resist film having a thickness of 0.4 μm. The resistfilm was subjected to pattern exposure using KrP excimer laser stepper(NA=0.42; 248 nm) and heated on a hot plate at 110° C. for 60 secondsimmediately after the exposure. Then the resist film was developed byimmersing it in a 2.38% aqueous tetramethylammonium hydroxide solutionat 23° C. for 60 seconds, rinsed with pure water for 30 seconds anddried.

[0310] A pattern form, sensitivity and resolution were evaluated witheach resist pattern obtained. Specifically, the pattern form wasdetermined by observation of the pattern obtained through a scanningelectron microscope and a pattern in a rectangular form was evaluatedgood.

[0311] The sensitivity was evaluated using an exposure amount necessaryfor reproducing a mask pattern of 0.35 μm.

[0312] The resolution was evaluated using limiting resolution in anexposure amount necessary for reproducing a mask pattern of 0.35 μm.

[0313] As a result, with the sensitivity and resolution as shown inTable 10 below, good positive pattern wherein only the exposed portionof the resist film was dissolved out was obtained. TABLE 10 Resin of thePresent Sensitivity Resolution Pattern Invention (mJ/cm²) (μm) Form(P1)  25 0.26 good (P2)  20 0.27 good (P3)  26 0.25 good (P4)  23 0.26good (P5)  19 0.25 good (P6)  20 0.27 good (P7)  26 0.25 good (P8)  280.26 good (P9)  21 0.27 good (P10) 27 0.25 good Polymer (2) 37 0.30 goodPolymer (3) 35 0.30 good

[0314] It can be seen from the results shown in Table 10 that the resistusing the resin according to the present invention exhibits highsensitivity and good resolution. Further, a good pattern form isobtained using the resin according to the present invention.

Example 9

[0315] Evaluation of Image

[0316] On each of the resist films having a thickness of 0.4 μm obtainedin Example 8, a mask prepared by drawing a pattern with chromium on aquartz plate was closely contacted and an ArF excimer laser beam (193nm) was irradiated thereto. The resist film was heated on a hot plate at110° C. for 60 seconds immediately after the exposure. Then the resistfilm was developed by immersing it in a 2.38% aqueoustetramethylammonium hydroxide solution at 23° C. for 60 seconds, rinsedwith pure water for 30 seconds and dried. As a result, with thesensitivity and resolution as shown in Table 11 below, good positivepattern wherein only the exposed portion of the resist film wasdissolved out was obtained. The evaluations were conducted in the samemanner as described above. TABLE 11 Resin of the Present SensitivityResolution Invention (mJ/cm²) (μm) Pattern Form (P1) 22 0.23 good (P2)16 0.23 good (P3) 23 0.23 good (P4) 22 0.23 good (P5) 17 0.23 good (P6)20 0.23 good (P7) 23 0.23 good (P8) 25 0.23 good (P9) 20 0.23 good(P10)  24 0.23 good Polymer (2) 33 0.27 good Polymer (3) 30 0.27 good

[0317] It can be seen from the results shown in Table 11 that the resistusing the resin according to the present invention exhibits goodsensitivity and resolution and forms a good positive pattern in case ofusing an ArF excimer laser beam.

[0318] As is apparent from the description above, the positivephotosensitive composition containing the resin according to the presentinvention has high transmittance to far ultraviolet light particularlyhaving a wavelength of 220 nm or less and exhibits good dry etchingresistance. Further, the positive photosensitive composition exhibitshigh sensitivity, good resolution and good pattern profile when farultraviolet light having a wavelength of 250 nm or less, particularly220 nm or less (especially an ArF excimer laser beam) is employed as anexposure light source, and thus it can be effectively employed for theformation of fine pattern necessary for the production of semiconductorelements.

[0319] While the invention has been described in detail and withreference to specific embodiments thereof, it will be apparent to oneskilled in the art that various changes and modifications can be madetherein without departing from the spirit and scope thereof.

What is claimed is:
 1. A positive photosensitive composition comprising(A) a compound which generates an acid upon irradiation with an actinicray or radiation, and (B) a resin having a group which is decomposed bythe action of an acid to increase solubility in an alkaline developingsolution, wherein the resin contains at least one structure representedby the following formulae (I), (II) and (III):

wherein R₁ and R₂, which may be the same or different, each represents ahydrogen atom or an optionally substituted straight-chain, branchedchain or cyclic alkyl group, or R₁ and R₂ may be bonded to each other toform a monocyclic or polycyclic ring which may contain an oxygen atom, asulfur atom, a nitrogen atom, a ketone bond, an ester bond, an imidobond or an amido bond as a linking group; R₃, R₄ and R₅, which may bethe same or different, each represents a hydrogen atom, an optionallysubstituted straight-chain, branched chain or cyclic alkyl or alkoxygroup, or two or more of R₃, R₄ and R₅ may be bonded to each other toform a monocyclic or polycyclic ring which may contain an oxygen atom, asulfur atom, a nitrogen atom, a ketone bond, or an ester bond as alinking group; X represents a single bond or a divalent linking group,or X and either or both of R₁ and R₂ may be bonded to each other to forma monocyclic or polycyclic ring; Y represents an oxygen atom, a sulfuratom, —NH—, —N(OH)— or —N(alkyl)—; and n represents an integer of from 1to
 3. 2. A positive photosensitive composition comprising (A) a compoundwhich generates an acid upon irradiation with an actinic ray orradiation, (B) a resin having a group which is decomposed by the actionof an acid to increase solubility in an alkaline developing solution,and (C) a low molecular weight compound having a molecular weight of3,000 or less and having a group which is decomposed by the action of anacid to increase solubility in an alkaline developing solution, whereinthe resin (B) and/or the low molecular weight compound (C) contain atleast one structure represented by formulae (I), (II) and (III):

wherein R₁ and R₂, which may be the same or different, each represents ahydrogen atom or an optionally substituted straight-chain, branchedchain or cyclic alkyl group, or R₁ and R₂ may be bonded to each other toform a monocyclic or polycyclic ring which may contain an oxygen atom, asulfur atom, a nitrogen atom, a ketone bond, an ester bond, an imidobond or an amido bond as a linking group; R₃, R₄ and R₅, which may bethe same or different, each represents a hydrogen atom, an optionallysubstituted straight-chain, branched chain or cyclic alkyl or alkoxygroup, or two or more of R₃, R₄ and R₅ may be bonded to each other toform a monocyclic or polycyclic ring which may contain an oxygen atom, asulfur atom, a nitrogen atom, a ketone bond, or an ester bond as alinking group; X represents a single bond or a divalent linking group,or X and either or both of R₁ and R₂ may be bonded to each other to forma monocyclic or polycyclic ring; Y represents an oxygen atom, a sulfuratom, —NH—, —N(OH)— or —N(alkyl)—; and n represents an integer of from 1to
 3. 3. The positive photosensitive composition as claimed in claim 1,wherein the resin having a group which is decomposed by the action of anacid to increase solubility in an alkaline developing solution is (D) aresin which contains at least one repeating unit having the structurerepresented by formula (I), (II) or (III) and a repeating unit having amonoalicyclic or polyalicyclic hydrocarbon moiety.
 4. A positivephotosensitive composition comprising (A) a compound which generates anacid upon irradiation with an actinic ray or radiation, (C) a lowmolecular weight compound having a molecular weight of 3,000 or less andhaving a group which is decomposed by the action of an acid to increasesolubility in an alkaline developing solution, and (E) a resin which isinsoluble in water but soluble in an alkaline developing solution,wherein the low molecular weight compound (C) contains at least onestructure represented by formulae (I), (II) and (III):

wherein R₁ and R₂, which may be the same or different, each represents ahydrogen atom or an optionally substituted straight-chain, branchedchain or cyclic alkyl group, or R₁ and R₂ may be bonded to each other toform a monocyclic or polycyclic ring which may contain an oxygen atom, asulfur atom, a nitrogen atom, a ketone bond, an ester bond, an imidobond or an amido bond as a linking group; R₃, R₄ and R₅, which may bethe same or different, each represents a hydrogen atom, an optionallysubstituted straight-chain, branched chain or cyclic alkyl or alkoxygroup, or two or more of R₃, R₄ and R₅ may be bonded to each other toform a monocyclic or polycyclic ring which may contain an oxygen atom, asulfur atom, a nitrogen atom, a ketone bond, or an ester bond as alinking group; X represents a single bond or a divalent linking group,or X and either or both of R₁ and R₂ may be bonded to each other to forma monocyclic or polycyclic ring; Y represents an oxygen atom, a sulfuratom, —NH—, —N(OH)— or —N(alkyl)—; and n represents an integer of from 1to
 3. 5. The positive photosensitive composition as claimed in claim 1,wherein R₁ and R₂ each represents a substituent other than a hydrogenatom.
 6. The positive photosensitive composition as claimed in claim 1,wherein the composition further comprises (F) a fluorine-base and/orsilicon-base surface active agent.
 7. The positive photosensitivecomposition as claimed in claim 1, wherein the composition is suitablefor exposure using far ultraviolet light having a wavelength of 250 nmor less as an exposure light source.
 8. The positive photosensitivecomposition as claimed in claim 1, wherein the composition is suitablefor exposure using far ultraviolet light having a wavelength of 220 nmor less as an exposure light source.
 9. A positive photosensitivecomposition comprising (A) a compound which generates an acid uponirradiation with an actinic ray or radiation and (B) a resin having atleast one monovalent polyalicyclic group represented by the followingformula (Ib) and a group which is decomposed by the action of an acid toincrease solubility in an alkaline developing solution:

wherein R_(a), R_(b), R_(c), R_(d), R_(e), R_(f) and R_(g), which may bethe same or different, each represents an optionally substituted alkyl,cycloalkyl, alkenyl or alkynyl group, a halogen atom, a cyano group,—R_(6b)—O—R_(7b), —R_(8b)—CO—O—R_(9b), —R_(10b)—CO—NR_(11b)R_(12b) or—R_(13b)—O—CO—R_(14b); R_(7b) and R_(9b), which may be the same ordifferent, each represents a hydrogen atom, an optionally substitutedalkyl, cycloalkyl or alkenyl group or a group which is decomposed by theaction of an acid to increase solubility in an alkaline developingsolution; R_(11b), R_(12b) and R_(14b), which may be the same ordifferent, each represents a hydrogen atom, an optionally substitutedalkyl, cycloalkyl or alkenyl group, or R_(11b) and R_(12b) may be bondedto each other to form a ring; R_(6b), R_(8b), R_(10b) and R_(13b), whichmay be the same or different, each represents a single bond, anoptionally substituted alkylene, alkenylene or cycloalkylene group; twoof R_(a) to R_(g), which are present on the same carbon atom, mayrepresent in combination a carbonyl group (═O) or a thiocarbonyl group(═S); two of R_(a) to R_(g), which are bonded to adjacent carbon atoms,may be bonded to each other to form a double bond between these twocarbon atoms; at least two of R_(a) to R_(g) may be bonded to each otherto form a ring; and the monovalent polyalicyclic group represented byformula (Ib) may be connected to the resin moiety in any positionthereof.
 10. The positive photosensitive composition as claimed in claim9, wherein the resin (B) is a resin comprising at least one repeatingunit represented by the following formulae (IVb), (Vb) and (VIb) and agroup which is decomposed by the action of an acid to increasesolubility in an alkaline developing solution:

wherein R_(15b), R_(16b) and R_(18b) to R_(20b), which may be the sameor different, each represents a hydrogen atom, a halogen atom, a cyanogroup, an alkyl group or a haloalkyl group; R_(17b) represents a cyanogroup, —CO—OR_(27b) or —CO—NR_(28b)R_(29b); X_(1b), X_(2b) and X_(3b),which may be the same or different, each represents a single bond, anoptionally substituted divalent alkylene, alkenylene or cycloalkylenegroup, —O—, —SO₂—, —O—CO—R_(30b)—, —CO—O—R_(31b)—, or—CO—NR_(32b)—R_(33b)—; R_(27b) represents a hydrogen atom, an optionallysubstituted alkyl, cycloalkyl or alkenyl group, or a group which isdecomposed by the action of an acid to increase solubility in analkaline developing solution; R_(28b), R_(29b) and R_(32b), which may bethe same or different, each represents a hydrogen atom or an optionallysubstituted alkyl, cycloalkyl or alkenyl group, or R_(28b) and R_(29b)may be bonded to each other to form a ring; R_(30b), R_(31b) andR_(33b), which may be the same or different, each represents a singlebond or a divalent alkylene, alkenylene or cycloalkylene group, or adivalent group formed by combining each of these groups with an ether,ester, amido, urethane or ureido group; and Yb represents thepolyalicyclic group represented by formula (Ib).
 11. The positivephotosensitive composition as claimed in claim 10, wherein the resin (B)is a resin which is decomposed by the action of an acid to increasesolubility in an alkaline developing solution and has at least onerepeating unit represented by formulae (IVb), (Vb) and (VIb) and atleast one repeating unit represented by the following formulae (VIIb),(VIIIb) and (IXb):

wherein R_(21b), R_(22b) and R_(24b) to R_(26b), which may be the sameor different, each represents a hydrogen atom, a halogen atom, a cyanogroup, an alkyl group or a haloalkyl group; R_(23b) represents a cyanogroup, —CO—OR_(27b) or —CO—NR_(28b)R_(29b); X_(4b), X_(5b) and X_(6b),which may be the same or different, each represents a single bond, anoptionally substituted divalent alkylene, alkenylene or cycloalkylenegroup, —O—, —SO₂—, —O—CO—R_(30b)—, —CO—O—R_(31b)— or—CO—NR_(32b)—R_(33b)—; R_(27b) represents a hydrogen atom, an optionallysubstituted alkyl, cycloalkyl or alkenyl group, or a group which isdecomposed by the action of an acid to increase solubility in analkaline developing solution; R_(28b), R_(29b) and R_(32b), which may bethe same or different, each represents a hydrogen atom or an optionallysubstituted alkyl, cycloalkyl or alkenyl group, or R_(28b) and R_(29b)may be bonded to each other to form a ring; R_(30b), R_(31b) andR_(33b), which may be the same or different, each represents a singlebond or a divalent alkylene, alkenylene or cycloalkylene group, or adivalent group formed by combining each of these groups with an ether,ester, amido, urethane or ureido group; and B_(b) is a group which isdecomposed by the action of an acid to increase solubility in analkaline developing solution.
 12. The positive photosensitivecomposition as claimed in claim 9, wherein the resin (B) furthercomprises a carboxy group.
 13. The positive photosensitive compositionas claimed in claim 12, wherein the resin (B) further comprises at leastone repeating unit represented by the following formulae (Xb), (XIb) and(XIIb) each having a carboxy group:

wherein R_(34b), R_(35b) and R_(37b) to R_(39b), which may be the sameor different, each represents a hydrogen atom, a halogen atom, a cyanogroup, an alkyl group or a haloalkyl group; R_(36b) represents a cyanogroup, a carboxy group, —CO—OR_(40b) or —CO— NR_(41b)R_(42b); X_(7b),X_(8b) and X_(9b), which may be the same or different, each represents asingle bond, an optionally substituted divalent alkylene, alkenylene orcycloalkylene group, —O—, —SO₂—, —O—CO—R_(43b)—, —CO—O—R_(44b)— or—CO—NR_(45b)—R_(46b)—; R_(40b) represents an optionally substitutedalkyl, cycloalkyl or alkenyl group; R_(41b), R_(42b) and R_(45b), whichmay be the same or different, each represents a hydrogen atom or anoptionally substituted alkyl, cycloalkyl or alkenyl group, or R_(41b)and R_(42b) may be bonded to each other to form a ring; R_(43b), R_(44b)and R_(46b), which may be the same or different, each represents asingle bond or a divalent alkylene, alkenylene or cycloalkylene group,or a divalent group formed by combining each of these groups with anether, ester, amido, urethane or ureido group.
 14. The positivephotosensitive composition as claimed in claim 9, wherein thecomposition further comprises a low molecular weight acid-decomposabledissolution inhibiting compound whose solubility in an alkalinedeveloping solution increases by the action of an acid and which has agroup capable of being decomposed by the action of an acid and amolecular weight of 3,000 or less.
 15. The positive photosensitivecomposition as claimed in claim 9, wherein the composition is suitablefor exposure using far ultraviolet light having a wavelength of 250 nmor less as an exposure light source.
 16. The positive photosensitivecomposition as claimed in claim 15, wherein the composition is suitablefor exposure using far ultraviolet light having a wavelength of 220 nmor less as an exposure light source.
 17. The positive photosensitivecomposition as claimed in claim 1, wherein the resin having a groupwhich is decomposed by the action of an acid to increase solubility inan alkaline developing solution is a resin which contains at least onerepeating unit represented by the following formulae (IV), (V) and (VI):

wherein R₁₅, R₁₆ and R₁₈ to R₂₀, which may be the same or different,each represents a hydrogen atom, a halogen atom, a cyano group, an alkylgroup or a haloalkyl group; R₁₇ represents a cyano group, —CO—OR₂₇ or—CO—NR₂₈R₂₉; X₁, X₂ and X₃, which may be the same or different, eachrepresents a single bond, an optionally substituted divalent alkylene,alkenylene or cycloalkylene group, —CO—, —SO₂—, —O—CO—R₃₀—, —CO—O—R₃₁—,or —CO—NR₃₂—R₃₃—; R₂₇ represents a hydrogen atom, an optionallysubstituted alkyl, cycloalkyl or alkenyl group, or a group which isdecomposed by the action of an acid to increase solubility in analkaline developing solution; R₂₈, R₂₉ and R₃₂, which may be the same ordifferent, each represents a hydrogen atom or an optionally substitutedalkyl, cycloalkyl or alkenyl group, or R₂₈ and R₂₉ may be bonded to eachother to form a ring; R₃₀, R₃₁ and R₃₃, which may be the same ordifferent, each represents a single bond or a divalent alkylene,alkenylene or cycloalkylene group, or a divalent group formed bycombining each of these groups with an ether, ester, amido, urethane orureido group; and Y represents the structure represented by formula (I),(II) or (III) as described in claim
 1. 18. The positive photosensitivecomposition as claimed in claim 1, wherein the group which is decomposedby the action of an acid to increase solubility in an alkalinedeveloping solution is a group represented by the following formula(XIII) or (XIV):

wherein R₄₇ to R₄₉, which may be the same or different, each representsa hydrogen atom or an optionally substituted alkyl, cycloalkyl oralkenyl group, provided that at least one of R₄₇ to R₄₉ in formula(XIII) is not a hydrogen atom; R₅₀ represents an optionally substitutedalkyl, cycloalkyl, or alkenyl group; or two of R₄₇ to R₄₉ in formula(XIII) or two of R₄₇, R₄₈, and R₅₀ in formula (XIV) may be bonded toeach other to form a three- to eight-membered cyclic structurecomprising carbon atoms and optionally containing one or moreheteroatoms; and Z₁ and Z₂, which may be the same or different, eachrepresents an oxygen atom or a sulfur atom.
 19. The positivephotosensitive composition as claimed in claim 3, wherein the repeatingunit having a monoalicyclic or polyalicyclic hydrocarbon moiety is arepeating unit represented by the following formula (VII),

wherein R₃₅, R₃₆ and R₃₈ to R₄₀, which may be the same or different,each represents a hydrogen atom, a halogen atom, a cyano group, an alkylgroup or a haloalkyl group; R₃₇ represents a cyano group, —CO—OR₄₇ or—CO—NR₄₈R₄₉; X₄, X₅ and X₆, which may be the same or different, eachrepresents a single bond, an optionally substituted divalent alkylene,alkenylene or cycloalkylene group, —CO—, —SO₂—, —O—CO—R₅₀—, —CO—O—R₅₁—,or —CO—NR₅₂—R₅₃—; R₄₇ represents a hydrogen atom, an optionallysubstituted alkyl, cycloalkyl or alkenyl group, or a group which isdecomposed by the action of an acid to increase solubility in analkaline developing solution; R₄₈, R₄₉ and R₅₂, which may be the same ordifferent, each represents a hydrogen atom or an optionally substitutedalkyl, cycloalkyl or alkenyl group, or R₄₈ and R₄₉ may be bonded to eachother to form a ring; R₅₀, R₅₁ and R₅₃, which may be the same ordifferent, each represents a single bond or a divalent alkylene,alkenylene or cycloalkylene group, or a divalent group formed bycombining each of these groups with an ether, ester, amido, urethane orureido group; and A represents a monoalicyclic or polyalicyclic group.20. The positive photosensitive composition as claimed in claim 1,wherein the resin (B) comprises at least one repeating unit representedby the following formulae (X), (XI) and (XII):

wherein R₅₅, R₅₆ and R₅₈ to R₆₀, which may be the same or different,each represents a hydrogen atom, a halogen atom, a cyano group, an alkylgroup or a haloalkyl group; R₅₇ represents a cyano group, —CO—OR₆₇ or—CO—NR₆₈R₆₉; X₇, X₈ and X₉, which may be the same or different, eachrepresents a single bond, an optionally substituted divalent alkylene,alkenylene or cycloalkylene group, —CO—, —SO₂—, —O—CO—R₇₀—, —CO—O—R₇₁—or —CO—NR₇₂—R₇₃—; R₆₇ represents a hydrogen atom, an optionallysubstituted alkyl, cycloalkyl or alkenyl group, or a group which isdecomposed by the action of an acid to increase solubility in analkaline developing solution; R₆₈, R₆₉ and R₇₂, which may be the same ordifferent, each represents a hydrogen atom or an optionally substitutedalkyl, cycloalkyl or alkenyl group, or R₆₈ and R₆₉ may be bonded to eachother to form a ring; R₇₀, R₇₁ and R₇₃, which may be the same ordifferent, each represents a single bond or a divalent alkylene,alkenylene or cycloalkylene group, or a divalent group formed bycombining each of these groups with an ether, ester, amido, urethane orureido group; and B is a group which is decomposed by the action of anacid to increase solubility in an alkaline developing solution.
 21. Thepositive photosensitive composition as claimed in claim 1, wherein theresin (B) further comprises a carboxy group.
 22. The positivephotosensitive composition as claimed in claim 1, wherein the resin (B)further comprises at least one repeating unit represented by thefollowing formulae (XV), (XVI) and (XVII):

wherein R₇₅, R₇₆ and R₇₈ to R₈₀, which may be the same or different,each represents a hydrogen atom, a halogen atom, a cyano group, an alkylgroup or a haloalkyl group; R₇₇ represents a cyano group, —CO—OR₈₇ or—CO—NR₈₈R₈₉; X₁₀, X₁₁ and X₁₂, which may be the same or different, eachrepresents a single bond, an optionally substituted divalent alkylene,alkenylene or cycloalkylene group, —CO—, —SO₂—, —O—CO—R₉₀—, —CO—O—R₉₁—or —CO—NR₉₂—R₉₃—; R₈₇ represents a hydrogen atom, an optionallysubstituted alkyl, cycloalkyl or alkenyl group, or a group which isdecomposed by the action of an acid to increase solubility in analkaline developing solution; R₈₈, R₈₉ and R₉₂, which may be the same ordifferent, each represents a hydrogen atom or an optionally substitutedalkyl, cycloalkyl or alkenyl group, or R₈₈ and R₈₉ may be bonded to eachother to form a ring; and R₉₀, R₉₁ and R₉₃, which may be the same ordifferent, each represents a single bond or a divalent alkylene,alkenylene or cycloalkylene group, or a divalent group formed bycombining each of these groups with an ether, ester, amido, urethane orureido group.
 23. The positive photosensitive composition as claimed inclaim 3, wherein the monoalicyclic or polyalicyclic hydrocarbon moietyis an adamantane residue.
 24. The positive photosensitive composition asclaimed in claim 1, wherein the resin having a group which is decomposedby the action of an acid to increase solubility in an alkalinedeveloping solution contains a structure represented by formula (a):

R₁ and R₂, which may be the same or different, each represents ahydrogen atom or an optionally substituted straight-chain, branchedchain or cyclic alkyl group, or R₁ and R₂ may be bonded to each other toform a monocyclic or polycyclic ring which may contain an oxygen atom, asulfur atom, a nitrogen atom, a ketone bond, an ester bond, an imidobond or an amido bond as a linking group; R₃, R₄ and R₅, which may bethe same or different, each represents a hydrogen atom, an optionallysubstituted straight-chain, branched chain or cyclic alkyl or alkoxygroup, or two or more of R₃, R₄ and R₅ may be bonded to each other toform a monocyclic or polycyclic ring which may contain an oxygen atom, asulfur atom, a nitrogen atom, a ketone bond, or an ester bond as alinking group; R₁₅ represents a hydrogen atom, a halogen atom, a cyanogroup, an alkyl group or a haloalkyl group; and n represents an integerof from 1 to
 3. 25. The positive photosensitive composition as claimedin claim 1, wherein the resin having a group which is decomposed by theaction of an acid to increase solubility in an alkaline developingsolution contains a structure represented by formula (b):

R₁ and R₂, which may be the same or different, each represents ahydrogen atom or an optionally substituted straight-chain, branchedchain or cyclic alkyl group, or R₁ and R₂ may be bonded to each other toform a monocyclic or polycyclic ring which may contain an oxygen atom, asulfur atom, a nitrogen atom, a ketone bond, an ester bond, an imidobond or an amido bond as a linking group; R₃, R₄ and R₅, which may bethe same or different, each represents a hydrogen atom, an optionallysubstituted straight-chain, branched chain or cyclic alkyl or alkoxygroup, or two or more of R₃, R₄ and R₅ may be bonded to each other toform a monocyclic or polycyclic ring which may contain an oxygen atom, asulfur atom, a nitrogen atom, a ketone bond, or an ester bond as alinking group; R₁₅ represents a hydrogen atom, a halogen atom, a cyanogroup, an alkyl group or a haloalkyl group; and n represents an integerof from 1 to 3.